Jugular Bulb Venous Oxygen Saturation During One-Lung Ventilation Under Sevoflurane- or Propofol-Based Anesthesia for Lung Surgery

Comparison of regional cerebral oxygen saturation during one-lung ventilation under desflurane or propofol anesthesia: A randomized trial

BACKGROUND

During one-lung ventilation (OLV), deterioration of pulmonary oxygenation reduces arterial oxygen saturation and cerebral oxygen saturation (rSO2). However, oxidative stress during OLV causes lung injury, so the fraction of inspiratory oxygen (FiO2) should be kept as low as possible. We investigated the changes in rSO2 under propofol or desflurane anesthesia while percutaneous oxygen saturation (SpO2) was kept as low as possible during OLV.

METHODS

Thirty-six patients scheduled for thoracic surgery under OLV in the lateral decubitus position were randomly assigned to propofol (n = 19) or desflurane (n = 17) anesthesia. FiO2 was set to 0.4 at the start of surgery under two-lung ventilation (measurement point: T3) and then adjusted to maintain an SpO2 of 92% to 94% after the initiation of OLV. The primary outcome was the difference in the absolute value of the decrease in rSO2 from T3 to 30 minutes after the initiation of OLV (T5), which was analyzed by an analysis of covariance adjusted for the rSO2 value at T3.

RESULTS

The mean rSO2 values were 61.5% ± 5.1% at T3 and 57.1% ± 5.3% at T5 in the propofol group and 62.2% ± 6.0% at T3 and 58.6% ± 5.3% at T5 in the desflurane group. The difference in the absolute value of decrease between groups (propofol group - desflurane group) was 0.95 (95% confidence interval, [-0.32, 2.2]; P = .152).

CONCLUSIONS

Both propofol and desflurane anesthesia maintain comparable cerebral oxygenation and can be used safely, even when the SpO2 is kept as low as possible during OLV.

Inhalational versus intravenous anesthetics during one lung ventilation in elective thoracic surgeries: A narrative review

The anesthesia regimen used during one lung ventilation (OLV) carry the potential to affect intra-operative course and post-operative outcomes, by its effects on pulmonary vasculature and alveolar inflammation. This narrative review aims to understand the pathophysiology of acute lung injury during one lung ventilation, and to study the effects of inhalational versus intravenous anaesthetics on intraoperative and post-operative outcomes, following thoracic surgery. For this purpose, we independently searched 'PubMed', 'Google Scholar' and 'Cochrane Central' databases to find out randomized controlled trials (RCTs), in English language, which compared the effects of intravenous versus inhalational anaesthetics on intraoperative and post-operative outcomes, in elective thoracic surgeries, in human beings. In total, 38 RCTs were included in this review. Salient results of the review are- Propofol reduced intraoperative shunt and maintained better intraoperative oxygenation than inhalational agents. However, use of modern inhalational anaesthetics during OLV reduced alveolar inflammation significantly, as compared to propofol. Regarding post-operative complications, the evidence is not conclusive enough but slightly in favour of inhalational anaesthetics. Thus, we conclude that modern inhalational anaesthetics, by their virtue of better anti-inflammatory properties, exhibit lung protective effects and hence, seem to be safe for maintenance of anesthesia during OLV in elective thoracic surgeries. Further research is required to establish the safety of these agents with respect to long term post-operative outcomes like cancer recurrence.

Cerebral Perfusion and Brain Oxygen Saturation Monitoring with: Jugular Venous Oxygen Saturation, Cerebral Oximetry, and Transcranial Doppler Ultrasonography

Accumulating evidence indicates that cerebral desaturation in the perioperative period occurs more frequently than recognized. Combining monitoring modalities that reflect different aspects of cerebral perfusion status, such as near-infrared spectroscopy, jugular bulb saturation, and transcranial Doppler ultrasonography, may provide an extended window for prevention, early detection, and prompt intervention in ongoing hypoxic/ischemic neuronal injury and, thereby, improve neurologic outcome. Such an approach would minimize the impact of limitations of each monitoring modality, while individual components complement each other, enhancing the accuracy of acquired information. Current literature has failed to demonstrate any clear-cut clinical benefit of these modalities on outcome prognosis.

Comparison of the effect of sevoflurane or propofol anesthesia on the regional cerebral oxygen saturation in patients undergoing carotid endarterectomy: a prospective, randomized controlled study

Background

The monitoring of regional cerebral oxygen saturation (SrO₂) using near-infrared spectroscopy is useful method to detect cerebral ischemia during. Sevoflurane and propofol decrease cerebral metabolic rate (CMRO₂) in a similar manner, but the effects on the cerebral blood flow (CBF) are different. We hypothesized that the effects of sevoflurane and propofol on SrO₂ were different in patients with deficits of CBF. This study compared the effect of sevoflurane and propofol on SrO₂ of patients undergoing cerebral endarterectomy (CEA).

Method

Patients undergoing CEA were randomly assigned to the sevoflurane or propofol group (n = 74). The experiment was preceded in 2 stages based on carotid artery clamping. The first stage was from induction of anaesthesia to immediately before clamping of the carotid artery, and the second stage was until the end of the operation after clamping of the carotid artery. Oxygen saturation (SrO₂, SpO₂), haemodynamic variables (blood pressure, heart rate), respiratory parameters (end-tidal carbon dioxide tension, inspired oxygen tension), concentration of anesthetics, and anesthesia depth (bispectral index score) were recorded.

Results

During stage 1 period (before carotid artery clamping), the mean value of the relative changes in SrO₂ was higher (P = 0.033) and the maximal decrease in SrO₂ was lower in the sevoflurane group compared with the propofol group (P = 0.019) in the contralateral (normal) site. However, there is no difference in ipsilateral site (affected site). SrO₂ decreased after carotid artery clamping and increased after declamping, but the difference was not significant between two groups. Changes in mean arterial blood pressure was lower in sevoflurane group than propofol group after the carotid artery declamping (P = 0.048).

Conclusion

Propofol-remifentanil anesthesia was comparable with sevoflurane-remifentanil anesthesia in an aspect of preserving the SrO₂ in patients undergoing carotid endarterectomy.

Trial registration

Clinical Trials.gov identifier: NCT02609087, retrospectively registered on November 18, 2015.

Protective effects of dexmedetomidine on lung in rats with one-lung ventilation

Protective effect of dexmedetomidine (DEX) on the lungs of one-lung ventilation (OLV) rat model and its effect on inflammatory factors were investigated. Ninety-two rats were selected and divided into groups A, B, C and D (n=23) according to the principle of similar body weight. OLV rat model was established. Before modeling (15 min), rats in group C were injected with sodium chloride. Rats in group D were injected with DEX at a speed of 5 µg/kg/h. Group A rats were ventilated in both lungs for 2 h. Rats in groups B and C (0.9% sodium chloride injection + OLV) and in group D (DEX + OLV) were subjected to OLV for 2 h and bilateral ventilation for 10 min. Concentrations of interleukin (IL)-6, IL-10 and tumor necrosis factor-α (TNF-α) in lung tissue of rats were detected by ELISA. The malondialdehyde (MDA) concentration and superoxide dismutase (SOD) activity in rat lung tissue were detected by radioimmunoassay. Wet weight (W)/dry weight (D) of lung tissue was calculated and indexes of the four groups of rats were compared. Compared with group A, IL-6, TNF-α and MDA concentrations and W/D of lung tissue of rats in groups B, C and D were significantly increased (p<0.05); SOD activity and IL-10 concentration were significantly decreased (p<0.01). Compared with groups B and C, the concentrations of IL-6, TNF-α and W/D in rats of group D were significantly decreased (p<0.01), but IL-10 significantly increased (p<0.01). Compared with groups B and C, the MDA concentration in lung tissue of rats in group D was significantly decreased (p<0.01), but SOD activity significantly increased (p<0.01). DEX can inhibit the production of inflammatory factors in the development and progression of pulmonary inflammation. It can inhibit lipid peroxidation, relieve pulmonary edema, and reduce lung injury after OLV, sin order to protect the lung.

Effect of propofol and isoflurane on gas exchange parameters following one-lung ventilation in thoracic surgery: a double-blinded randomized controlled clinical trial

Background

The use of anesthetic drugs with minimal inhibitory effects on the hypoxic pulmonary vasoconstriction (HPV) could have a decisive role in preventing the hypoxemia during one-lung ventilation (OLV).

Objective

The aim of this study was to compare the effects of propofol and isoflurane on the changes in gas exchange parameters following OLV in thoracic surgery.

Methods

This double-blinded randomized controlled clinical trial was conducted on patients who were candidates for elective right thoracotomy referred to the central operating room of Ghaem Hospital in Mashhad, Iran, during February 2016–2017. Patients with age range of 18 to 75 years, class I and II American Society of Anesthesiologists (ASA) and thoracotomy with OLV for pulmonary resection or cyst drainage were included. The patients were randomly allocated (1:1 ratio) into two groups of propofol (P, 50–100μg/kg/min) and isoflurane (I, 1 minimum alveolar concentration (MAC) 1.1%). Partial pressure of carbon dioxide (PaCO2), partial pressure of oxygen (PaO2), end-tidal carbon dioxide (ETCO2) and arterial oxygen saturation (SPO2) were recorded before and 15 minutes after OLV and compared between the two groups. The comparison of the mean gas exchange parameters before and 15 minutes after OLV was performed using Mann-Whitney test in SPSS version 19 software. P<0.05 was considered statistically significant.

Results

In this study, 122 patients with mean age of 59.4±14.1 years (two groups of 61) were studied. Both groups were matched for age or gender. The two groups had no significant difference in the gas exchange parameters before the OLV. Only PaCO2 (p=0.001) and ETCO2 (p=0.001) were significantly higher in the propofol group after 15 minutes OLV than in the isoflurane group. However, PaO2 (p=0.67), O2Sat (p=0.333) and PaCO2-ETCO2 gradient (p=0.809) showed no significant difference between the two groups at this minute.

Conclusion

Based on the results of this study, the propofol or isoflurane selection seems to have no significant effect on the arterial oxygenation. On the other hand, isoflurane and propofol could be an appropriate anesthetic for thoracic surgery by normalizing the carbon dioxide gradient range during the OLV.

Clinical Trial Registration

The study was also registered at the Iranian Registry of Clinical Trials (IRCT2015123013159N8).

Funding

The study was financially supported by the Deputy of Research of Mashhad University of Medical Sciences (grant number: 940119).

Background anaesthetic agents do not influence the impact of arginine vasopressin on haemodynamic states and cerebral oxygenation during shoulder surgery in the beach chair position: a prospective, single-blind study

BACKGROUND

Administration of arginine vasopressin (AVP) is associated with reducing jugular venous (SjvO₂) and regional cerebral (rScO₂) oxygen saturation under propofol-remifentanil (P/R) anaesthesia. We determined whether background anaesthetics modulate the effect of AVP on cerebral oxygenation and haemodynamics.

METHODS

We randomly allocated 60 adult patients scheduled for shoulder surgery in the beach chair position (BCP) into 4 groups, to receive either an intravenous bolus of saline (groups PR-S and SN-S) or 0.05 U/kg AVP (groups PR-AVP and SN-AVP) under P/R or sevoflurane-nitrous oxide (S/N) anaesthesia (n = 15 each). Haemodynamic variables, SjvO₂ and rScO₂ were measured.

RESULTS

AVP significantly increased mean arterial blood pressure (MAP) and decreased rScO₂ in either anaesthetic group. AVP also decreased SjvO₂ in the P/R groups but not in the S/N groups. The AVP-treated groups showed higher MAP and cerebral desaturation (>20% rScO₂ decrease from baseline), along with lower HR and rScO₂ in the BCP than those in the saline-treated groups. In contrast, AVP did not affect SjvO₂ values or the incidence of SjvO ₂  < 50%. Baseline SjvO₂ was lower and the magnitude of its reduction in the BCP was greater in the PR-AVP group than in the SN-AVP group, and the lowest SjvO₂ values were 37 ± 6 and 57 ± 8%, respectively (P < 0.001).

CONCLUSIONS

The choice of anaesthetic regimen did not affect cerebral oxygenation or haemodynamics of AVP in the BCP. However, the negative effect of AVP on cerebral oxygenation should be considered, especially under P/R anaesthesia.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01687894 , registered on September 18, 2012.

Sevoflurane preserves regional cerebral oxygen saturation better than propofol: Randomized controlled trial

STUDY OBJECTIVE

To investigate possible effects of volatile induction and maintenance anesthesia with sevoflurane (VIMA) and total intravenous anesthesia with propofol (TIVA) on regional cerebral oxygen saturation (rcSo₂) during laparoscopic cholecystectomy.

DESIGN

Randomized, prospective and single-blinded study.

SETTING

Academic hospital.

PATIENTS

ASA physical status of I and II surgical patients, scheduled for elective laparoscopic cholecystectomy from March 2013 to October 2014.

MEASUREMENTS

Changes of regional cerebral oxygen saturation were measured by near-infrared spectroscopy on the left and right sides of forehead at different time points: before anesthesia induction (Tbas), immediately after induction (Tind), after applaying a pneumoperitoneum (TCo₂), 10 minutes after positioning the patient into reverse Trendelenburg's position (TrtCo₂), immediately after desufflation of gas (Tpost) and 30 (Trec30) and 60 (Trec60) minutes after emergence from anesthesia.

MAIN RESULTS

Study population included 124 patients, 62 in each group. There was no significant difference between these groups according to demographic characteristics, surgery and anesthesia times as well as in the basal rcSo₂ values. Statistically higher rSco₂ values were noted in the VIMA group when compared to the TIVA group in all time points Tind, TCo₂, TrtCo₂, Tpost, Trec30 and Trec60 and incidence of critical rcSo₂ decreases was statistically lower in VIMA group (P<.05). There were no serious perioperative complications.

CONCLUSIONS

VIMA technique provides significantly (4%-11%) higher rcSO₂ values during general anesthesia for laparoscopic cholecystectomy, when compared with TIVA and also provides significantly less number of critical rcSO₂ decreases.

A comparative analysis of the effects of sevoflurane and propofol on cerebral oxygenation during steep Trendelenburg position and pneumoperitoneum for robotic-assisted laparoscopic prostatectomy

Purpose

Steep Trendelenburg position and pneumoperitoneum during robotic-assisted laparoscopic prostatectomy (RALP) increase intracranial pressure (ICP) and may alter cerebral blood flow (CBF) and oxygenation. Volatile anesthetics and propofol have different effects on ICP, CBF, and cerebral metabolic rate and may have different impact on cerebral oxygenation during RALP. In this study, we measured jugular venous bulb oxygenation (SjO₂) and regional oxygen saturation (SctO₂) in patients undergoing RALP to evaluate cerebral oxygenation and compared the effects of sevoflurane and propofol. We also verified whether SctO₂ may be an alternative to SjO₂.

Methods

Fifty patients scheduled for RALP were randomly assigned to undergo sevoflurane (group S) or propofol (group P) anesthesia. SjO₂, SctO₂, mean arterial pressure (MAP), heart rate (HR), cardiac index (CI), central venous pressure (CVP), partial pressures of arterial oxygen (PaO₂) and carbon dioxide (PaCO₂), hemoglobin concentration (Hb), Bispectral Index (BIS) and nasopharyngeal temperature (BT) were recorded 5 min before surgery commencement, 5 min after pneumoperitoneum, 5, 30, 60, 90, and 120 min after pneumoperitoneum in a Trendelenburg position, and after desufflation in a supine position.

Results

SjO₂ was significantly higher in group S than in group P at all measurement points [group S vs. group P: 77 % (11) vs. 65 % (13), mean of all measurement points (1SD); p < 0.01]. Linear regression analysis (β = 0.106; r² = 0.065; p = 0.004) shows a weak relationship between SjO₂ and SctO₂.

Conclusions

Sevoflurane maintains higher SjO₂ levels than propofol during RALP. SctO₂ does not accurately reflect SjO₂.

Influence of Ventilation Strategies and Anesthetic Techniques on Regional Cerebral Oximetry in the Beach Chair Position: A Prospective Interventional Study with a Randomized Comparison of Two Anesthetics

BACKGROUND

Beach chair positioning during general anesthesia is associated with cerebral oxygen desaturation. Changes in cerebral oxygenation resulting from the interaction of inspired oxygen fraction (FIO2), end-tidal carbon dioxide (PETCO2), and anesthetic choice have not been fully evaluated in anesthetized patients in the beach chair position.

METHODS

This is a prospective interventional within-group study of patients undergoing shoulder surgery in the beach chair position that incorporated a randomized comparison between two anesthetics. Fifty-six patients were randomized to receive desflurane or total intravenous anesthesia with propofol. Following induction of anesthesia and positioning, FIO2 and minute ventilation were sequentially adjusted for all patients. Regional cerebral oxygenation (rSO2) was the primary outcome and was recorded at each of five set points.

RESULTS

While maintaining FIO2 at 0.3 and PETCO2 at 30 mmHg, there was a decrease in rSO2 from 68% (SD, 12) to 61% (SD, 12) (P < 0.001) following beach chair positioning. The combined interventions of increasing FIO2 to 1.0 and increasing PETCO2 to 45 mmHg resulted in a 14% point improvement in rSO2 to 75% (SD, 12) (P <0.001) for patients anesthetized in the beach chair position. There was no significant interaction effect of the anesthetic at the study intervention points.

CONCLUSIONS

Increasing FIO2 and PETCO2 resulted in a significant increase in rSO2 that overcomes desaturation in patients anesthetized in the beach chair position and that appears independent of anesthetic choice.

Critical care strategies to improve neurocognitive outcome in thoracic surgery

PURPOSE OF REVIEW

This review focuses on neurocognitive outcome with respect to potential pathophysiological inflammatory mechanisms of thoracic surgery and one-lung ventilation, risk factors of postoperative delirium and postoperative cognitive dysfunction (POCD) as well as anti-inflammatory strategies.

RECENT FINDINGS

Neurocognitive dysfunction is associated with increased mortality and disability. The incidence of postoperative delirium and POCD is often underestimated in the perioperative care setting. Both are threatening complications after major surgery and independently associated with an increased morbidity and mortality. Nevertheless, in thoracic surgery, the clinical relevance of neurocognitive dysfunction is still underestimated. Currently, there has been a growing interest in inflammation as a cause of the pathogenesis of postoperative delirium and POCD. Furthermore, thoracic surgery often requires one-lung ventilation, which is accompanied with important physiological disturbances, and leads to a pulmonary arteriovenous shunt with the decrease of arterial oxygen content and an exaggerated activation of inflammatory processes. As inflammation is involved in brain dysfunction, anti-inflammatory strategies in the perioperative setting seem to be potential neuroprotective targets concerning specially high-risk patients undergoing thoracic surgery under one-lung ventilation.

SUMMARY

There is evidence that important key strategies improve neurocognitive outcome after thoracic surgery. This includes adequate risk stratification, the anesthetic management and postoperative critical care strategies.

Intravenous versus inhalation anaesthesia for one-lung ventilation

BACKGROUND

This is an update of a Cochrane Review first published in The Cochrane Library, Issue 2, 2008.The technique called one-lung ventilation can confine bleeding or infection to one lung, prevent rupture of a lung cyst or, more commonly, facilitate surgical exposure of the unventilated lung. During one-lung ventilation, anaesthesia is maintained either by delivering an inhalation anaesthetic to the ventilated lung or by infusing an intravenous anaesthetic. It is possible that the method chosen to maintain anaesthesia may affect patient outcomes. Inhalation anaesthetics may impair hypoxic pulmonary vasoconstriction (HPV) and increase intrapulmonary shunt and hypoxaemia.

OBJECTIVES

The objective of this review was to evaluate the effectiveness and safety of intravenous versus inhalation anaesthesia for one-lung ventilation.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL); The Cochrane Library (2012, Issue 11); MEDLINE (1966 to November 2012); EMBASE (1980 to November 2012); Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS, 1982 to November 2012) and ISI web of Science (1945 to November 2012), reference lists of identified trials and bibliographies of published reviews. We also contacted researchers in the field. No language restrictions were applied. The date of the most recent search was 19 November 2012. The original search was performed in June 2006.

SELECTION CRITERIA

We included randomized controlled trials and quasi-randomized controlled trials of intravenous (e.g. propofol) versus inhalation (e.g. isoflurane, sevoflurane, desflurane) anaesthesia for one-lung ventilation in both surgical and intensive care participants. We excluded studies of participants who had only one lung (i.e. pneumonectomy or congenital absence of one lung).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We contacted study authors for additional information.

MAIN RESULTS

We included in this updated review 20 studies that enrolled 850 participants, all of which assessed surgical participants－no studies investigated one-lung ventilation performed outside the operating theatre. No evidence indicated that the drug used to maintain anaesthesia during one-lung ventilation affected participant outcomes. The methodological quality of the included studies was difficult to assess as it was reported poorly, so the predominant classification of bias was 'unclear'.

AUTHORS' CONCLUSIONS

Very little evidence from randomized controlled trials suggests differences in participant outcomes with anaesthesia maintained by intravenous versus inhalational anaesthesia during one-lung ventilation. If researchers believe that the type of drug used to maintain anaesthesia during one-lung ventilation is important, they should design randomized controlled trials with appropriate participant outcomes, rather than report temporary fluctuations in physiological variables.

Managing hypoxemia during minimally invasive thoracic surgery

An ever-increasing number of thoracic procedures are being performed through minimally invasive techniques. Although the incidence of hypoxemia during one-lung ventilation (OLV) has decreased over the years, it remains an issue in roughly 10% of cases. Algorithms for the management of OLV hypoxemia have to be adapted to the thoracoscopic approach, in particular the need for optimal surgical exposure. With appropriate planning and caution, most of the treatment modalities for OLV hypoxemia can be applied to the thoracoscopy setting, with some modifications.

Clinical experience with intraoperative jugular venous oximetry during pediatric intracranial neurosurgery

AIM

To report our institutional experience with intraoperative jugular venous oximetry during pediatric intracranial surgery to guide anesthetic care.

BACKGROUND

The utility of intraoperative jugular venous oximetry in adults undergoing intracranial surgery is well known. However, there is a little information on its' application in children during intracranial surgery.

METHODS

After IRB approval, we examined patient, equipment, placement, and sampling characteristics for jugular bulb catheters in children aged <18 years who were monitored with jugular oximetry during elective intracranial surgery between 2006 and 2010. We also determined the prevalence of intraoperative cerebral desaturation (SjvO(2) < 55%), its causes, and the interventions based on jugular oximetry values.

RESULTS

Data from 19 children (10 males and nine females), aged 12 ± 1 years (range 7-17) who underwent craniotomy for arteriovenous malformation (AVM) resection (68%), tumor removal (21%), or aneurysm clipping (11%), were reviewed. We analyzed 88 coincident SjvO(2), PaCO(2), and mean arterial pressure data points. Eleven (58%) patients experienced at least one episode of cerebral desaturation. There were 25 (28%) episodes of cerebral desaturation, six of which we attributed to relative hypotension, four to hypocarbia, and 15 to a combination of both. There were no intraoperative or immediate postoperative (first 24 h) complications because of jugular oximetry.

CONCLUSION

Findings from this series indicate that (i) intraoperative jugular venous oximetry in children is feasible in experienced hands, (ii) cerebral desaturation detected by jugular oximetry is common during pediatric intracranial procedures, and (iii) monitoring jugular venous saturation can impact anesthetic interventions to optimize cerebral physiology.

A review of enhanced recovery for thoracic anaesthesia and surgery

During the past decade, there has been a dramatic increase in the number of thoracic surgical procedures carried out in the UK. The current financial climate dictates that more efficient use of resources is necessary to meet escalating demands on healthcare. One potential means to achieve this is through the introduction of enhanced recovery protocols, designed to produce productivity savings by driving reduction in length of stay. These have been promoted by government bodies in a number of surgical specialties, including colorectal, gynaecological and orthopaedic surgery. This review focuses on aspects of peri-operative care that might be incorporated into such a programme for thoracic anaesthesia, for which an enhanced recovery programme has not yet been introduced in the UK, and a review of the literature specific to this area of practice has not been published before. We performed a comprehensive search for published work relating to the peri-operative management and optimisation of patients undergoing thoracic surgery, and divided these into appropriate areas of practice. We have reviewed the specific interventions that may be included in an enhanced recovery programme, including: pre-optimisation; minimising fasting time; thrombo-embolic prophylaxis; choice of anaesthetic and analgesic technique and surgical approach; postoperative rehabilitation; and chest drain management. Using the currently available evidence, the design and implementation of an enhanced recovery programme based on this review in selected patients as a package of care may reduce morbidity and length of hospital stay, thus maximising utilisation of available resources.

Changes in cerebral oxygenation in patients with pulmonary dysfunction after lung resection

Lung resection would be associated with lower jugular bulb oxygen saturation (SjvO₂) values in patients with moderate to severe pulmonary dysfunction. We aimed to study the effects of lung resections on the postoperative changes in SjvO₂, incidence of SjvO₂ < 50%, pulmonary functions, cerebral blood flow equivalent (CBFE), and arterial to jugular difference in oxygen content (AjvDO₂) in the patients with pulmonary dysfunction. Fifty-three patients scheduled for lung resection were allocated on the basis of forced vital capacity (FVC %) and forced expiratory volume in 1 second (FEV(1)%) into the following: good FVC and FEV₁ (n = 14), mild (n = 14), moderate (n = 13), and severe (n = 12) pulmonary dysfunction groups. After lung resections, patients with pulmonary dysfunctions had significantly lower SjvO₂, CBFE, FEV₁, and FVC (P < .001), higher AjvDO₂ (P < .001), and frequent episodes with SjvO₂ < 50% (P < .03). Perioperative changes in FEV₁ had a significant negative correlation with SjvO₂ desaturation (P < .002). Patients with pulmonary dysfunction showed significant SjvO₂ < 50% after lung resection, which is correlated to the perioperative changes in FEV₁.

The influence of basic ventilation strategies and anesthetic techniques on cerebral oxygenation in the beach chair position: study protocol

Background

Beach chair positioning during general anesthesia is associated with a high incidence of cerebral desaturation; poor neurological outcome is a growing concern. There are no published data pertaining to changes in cerebral oxygenation seen with increases in the inspired oxygen fraction or end-tidal carbon dioxide in patients anesthetized in the beach chair position. Furthermore, the effect anesthetic agents have has not been thoroughly investigated in this context. We plan to test the hypothesis that changes in inspired oxygen fraction or end-tidal carbon dioxide correlate to a significant change in regional cerebral oxygenation in anesthetized patients in beach chair position. We will also compare the effects that inhaled and intravenous anesthetics have on this process.

Methods/design

This is a prospective within-group study of patients undergoing shoulder arthroscopy in the beach chair position which incorporates a randomized comparison between two anesthetics, approved by the Institutional Review Board of the University of Michigan, Ann Arbor. The primary outcome measure is the change in regional cerebral oxygenation due to sequential changes in oxygenation and ventilation. A sample size of 48 will have greater than 80% power to detect an absolute 4-5% difference in regional cerebral oxygenation caused by changes in ventilation strategy. The secondary outcome is the effect of anesthetic choice on cerebral desaturation in the beach chair position or response to changes in ventilation strategy. Fifty-four patients will be recruited, allowing for drop out, targeting 24 patients in each group randomized to an anesthetic. Regional cerebral oxygenation will be measured using the INVOS 5100C monitor (Covidien, Boulder, CO). Following induction of anesthesia, intubation and positioning, inspired oxygen fraction and minute ventilation will be sequentially adjusted. At each set point, regional cerebral oxygenation will be recorded and venous blood gas analysis performed. The overall statistical analysis will use a repeated measures analysis of variance with Tukey’s HSD procedure for post hoc contrasts.

Discussion

If simple maneuvers of ventilation or anesthetic technique can prevent cerebral hypoxia, patient outcome may be improved. This is the first study to investigate the effects of ventilation strategies on cerebral oxygenation in patients anesthetized in beach chair position.

Trial registration

NCT01535274

The effect of hypercapnia and hypertension on cerebral oxygen balance during one-lung ventilation for lung surgery during propofol anesthesia

STUDY OBJECTIVE

To investigate whether jugular bulb venous oxygen saturation (SjO(2)) values increased with induced hypercapnia or induced hypertension during propofol-based anesthesia for one-lung ventilation (OLV).

DESIGN

Prospective clinical study.

SETTING

Operating room at University hospital.

PARTICIPANTS

15 adult patients scheduled for elective thoracic procedures in the lateral position.

INTERVENTIONS

General anesthesia was maintained with propofol combined with epidural anesthesia. During OLV, hypercapnia (PaCO(2) = 50 mmHg) and hypertension (20% increase in mean arterial pressure) were applied.

MEASUREMENTS

SjO2 values were measured.

MAIN RESULTS

With hypercapnia, SjO(2) values increased 30 ± 18% (from 54.3 ± 8.8% to 69.3 ± 6.3%). With hypertension, SjO(2) values were increased by 9 ± 18% (from 54.4 ± 9.0% to 58.5 ± 8.8%). These changes were significantly different. No significant differences regarding SaO(2) were observed during OLV in the experimental period.

CONCLUSION

Hypercapnia, not hypertension, significantly improved cerebral oxygen balance without observed side effects during propofol anesthesia.

Significant decrease of cerebral oxygen saturation during single-lung ventilation measured using absolute oximetry

BACKGROUND

Single-lung ventilation (SLV) during thoracic surgery causes important cardiopulmonary disturbances. Absolute cerebral oximetry was used to determine the incidence and magnitude of the decrease in cerebral oxygen saturation (Sct(o(2))) in patients undergoing SLV during thoracic surgery.

METHODS

Data were obtained from 20 consecutive patients undergoing thoracic surgery and necessitating SLV of more than 1 h. The FORESIGHTtrade mark (CASMED, USA) absolute oximeter was used to measure left, right, and average absolute Sct(o(2)) every 5 min from the awake state to extubation. Bispectral index and standard monitoring parameters were also recorded every 5 min. Blood gas analysis was performed every 15 min. Data median (IQR) (range) were analysed using repeated-measures anova and Spearman's correlation test, P<0.05.

RESULTS

Patients [median age 65 yr (range 46-75)] showed an absolute Sct(o(2)) of 80% (78, 82) (74-87) in the awake state, which decreased to a minimum Sct(o(2)) value of 63% (57, 65) (53-73) during SLV to recover to an Sct(o(2)) of 71% immediately after extubation. During SLV, all patients had a decrease of more than 15% of the initial Sct(o(2)) and 70% of patients had a decrease of more than 20%. The decrease in Sct(o(2)) was not correlated with any standard clinical parameters, for example, arterial pressure, blood loss, peripheral oxygen saturation, or Pa(o(2)).

CONCLUSIONS

Thoracic surgery with SLV seems to be associated with a significant decrease of Sct(o(2)) in the majority of patients. Parameters such as peripheral oxygen saturation or Po(2) which are used to guide SLV during thoracic surgery are not sufficient to detect significant cerebral oxygen desaturations.