Effects of halothane, sevoflurane and propofol on left ventricular diastolic function in humans during spontaneous and mechanical ventilation

Effect of Sevoflurane Anesthesia on Diastolic Function: A Prospective Observational Study

BACKGROUND

The effect of sevoflurane on left ventricular diastolic function is not well understood. We hypothesized that parameters of diastolic function may improve under sevoflurane anesthesia in patients with preexisting diastolic dysfunction compared to patients with normal diastolic function.

METHODS

This observational study included 60 patients undergoing breast surgery or laparoscopic cholecystectomy. Patients were assigned to diastolic dysfunction (n = 34) or normal (n = 26) groups of septal e' < 8 or ≥ 8.0 cm/s on the first thoracic echocardiography (TTE) performed before anesthesia. During anesthesia, sevoflurane was maintained at 1 to 2 minimum alveolar concentration (MAC) to maintain the bispectral index at 40 to 50. At the end of surgery, the second TTE was performed under 0.8 to 1 MAC of sevoflurane with the patient breathing spontaneously without ventilator support. Primary end point was the percentage change (Δ) of e' on 2 TTEs (Δe'). Secondary end points were ΔE/e', Δleft atrial volume index (ΔLAVI), and Δtricuspid regurgitation maximum velocity (ΔTR Vmax). These percentage changes (Δ) were compared between diastolic dysfunction and normal groups.

RESULTS

e' (Δe': 30 [6, 64] vs 0 [-18, 11]%; P < .001), mitral inflow E wave velocity (E), mitral inflow E/A ratio (E/A), and mitral E velocity deceleration time (DT) improved significantly in diastolic dysfunction group compared to normal group. LAVI decreased in diastolic dysfunction group but did not reach statistical significance between the 2 groups (ΔLAVI:-15 [-31, -3] vs -4 [-20, 10]%, P = .091). ΔE/e' was not different between the 2 groups (11 [-16, 26] vs 12 [-9, 22]%, P = .853) (all: median [interquartile range, IQR]). TR was minimal in both groups.

CONCLUSIONS

In this study, echocardiographic parameters of diastolic function, including septal e', E, E/A, and DT, improved with sevoflurane anesthesia in patients with preexisting diastolic dysfunction, but remained unchanged in patients with normal diastolic function.

Remifentanil improves left ventricular diastolic parameters in patients with impaired diastolic function: a prospective clinical study

BACKGROUND

Left ventricular diastolic dysfunction has a significant impact on perioperative morbidity and mortality, and its incidence is high in elderly individuals. Anesthetic agents may impair diastolic function, which may increase the incidence of perioperative complications. The aim of this prospective, clinical, phase 4 study was to investigate the effects of remifentanil on left ventricle (LV) diastolic function in patients with diastolic dysfunction. The study was performed on 30 spontaneously breathing subjects (aged 60-80 years) with diastolic dysfunction.

METHODS

Thirty patients (aged 60-80 years) with diastolic dysfunction scheduled for surgery were recruited between November 2019 and March 2023. Left ventricle function was evaluated once the intravenous remifentanil infusion reached a target-controlled concentration of 2 ng/ml with transthoracic echocardiography. Analysis of systolic function focused on left ventricular ejection fraction and mean mitral annular S velocity (Sm), whereas diastolic function focused on changes in transmitral peak flow (E), E/A, mitral septal and lateral e' waves, E/e' ratios and left atrial volume index following remifentanil infusion.

RESULTS

Diastolic function measures of LV (mitral E/e', septal and lateral e' waves) statistically significantly improved (E/e' from 10.6 ± 2.9 cm.sn- 1 to 9.5 ± 2.2 cm.sn- 1; p = 0.006) following remifentanil infusion. Left atrial volume index decreased following remifentanil infusion without statistical significance (from 55 ± 14.4 ml.cm- 2 to 51.6 ± 13.3 ml.cm- 2; p = 0.1). Systolic function (ejection fraction and Sm) did not change following remifentanil infusion.

CONCLUSIONS

Remifentanil improves left ventricular diastolic parameters in patients with preexisting diastolic dysfunction. Our study suggests that remifentanil at a plasma concentration of 2 ng.ml- 1 might be used safely in patients with left ventricular diastolic dysfunction.

Consensus Defined Diastolic Dysfunction and Cardiac Postoperative Morbidity Score: A Prospective Observational Study

Diastolic dysfunction is associated with major adverse outcomes following cardiac surgery. We hypothesized that multisystem endpoints of morbidity would be higher in patients with diastolic dysfunction. A total of 142 patients undergoing cardiac surgical procedures with cardiopulmonary bypass were included in the study. Intraoperative assessments of diastolic function according to the 2016 American Society of Echocardiography and European Association of Cardiovascular Imaging guidelines using transesophageal echocardiography were performed. Cardiac Postoperative Morbidity Score (CPOMS) on days 3, 5, 8, and 15; length of stay in ICU and hospital; duration of intubation; incidence of new atrial fibrillation; 30-day major adverse cardiac and cerebrovascular events were recorded. Diastolic function was determinable in 96.7% of the dataset pre and poststernotomy assessment (n = 240). Diastolic dysfunction was present in 70.9% (n = 88) of measurements before sternotomy and 75% (n = 93) after sternal closure. Diastolic dysfunction at either stage was associated with greater CPOMS on D5 (p = 0.009) and D8 (p = 0.009), with CPOMS scores 1.24 (p = 0.01) higher than in patients with normal function. Diastolic dysfunction was also associated with longer durations of intubation (p = 0.001), ICU length of stay (p = 0.019), and new postoperative atrial fibrillation (p = 0.016, OR (95% CI) = 4.50 (1.22–25.17)). We were able to apply the updated ASE/EACVI guidelines and grade diastolic dysfunction in the majority of patients. Any grade of diastolic dysfunction was associated with greater all-cause morbidity, compared with patients with normal diastolic function.

Role of Echocardiography for the Perioperative Assessment of the Right Ventricle

Purpose of Review

This review aims to highlight the perioperative echocardiographic evaluation of right ventricular (RV) function with strengths and limitations of commonly used and evolving techniques. It explains the value of transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) and describes the perioperative changes of RV function echocardiographers should be aware of.

Recent Findings

RV dysfunction is an entity with strong influence on outcome. However, its definition and assessment in the perioperative interval are not well-defined. Moreover, values assessed by TTE and TEE are not interchangeable; while some parameters seem to correlate well, others do not. Myocardial strain analysis and three-dimensional echocardiography may overcome the limitations of conventional echocardiographic measures and provide further insight into perioperative cardiac mechanics.

Summary

Echocardiography has become an essential part of modern anesthesiology in patients with RV dysfunction. It offers the opportunity to evaluate not only global but also regional RV function and distinguish alterations of RV contraction.

Do Elderly Patients With Diastolic Dysfunction Require Higher Doses of Norepinephrine During General Anesthesia for Noncardiac Surgeries? A Prospective Observational Study

BACKGROUND

Diastolic dysfunction is a risk factor for postoperative major cardiovascular events. During anesthesia, patients with diastolic dysfunction might experience impaired hemodynamic function and worsening of diastolic function, which in turn, might be associated with a higher incidence of postoperative complications.We aimed to investigate whether patients with diastolic dysfunction require higher doses of norepinephrine during general anesthesia. Furthermore, we aimed to examine the association between the grade of diastolic dysfunction and the E/e' ratio during anesthesia. A high E/e' ratio corresponds to elevated filling pressures and is an important measure of impaired diastolic function.

METHODS

We conducted a prospective observational cohort study at a German university hospital from February 2017 to September 2018. Patients aged ≥60 years and undergoing general anesthesia (ie, propofol and sevoflurane) for elective noncardiac surgery were enrolled. Exclusion: mitral valve disease, atrial fibrillation, and implanted mechanical device.The primary outcome parameter was the administered dose of norepinephrine within 30 minutes after anesthesia induction (μg·kg-1 30 min-1). The secondary outcome parameter was the change of Doppler echocardiographic E/e' from ECHO1 (baseline) to ECHO2 (anesthesia). Linear models and linear mixed models were used for statistical evaluation.

RESULTS

A total of 247 patients were enrolled, and 200 patients (75 female) were included in the final analysis. Diastolic dysfunction at baseline was not associated with a higher dose of norepinephrine during anesthesia (P = .6953). The grade of diastolic dysfunction at baseline was associated with a decrease of the E/e' ratio during anesthesia (P < .001).

CONCLUSIONS

We did not find evidence for an association between diastolic dysfunction and impaired hemodynamic function, as expressed by high vasopressor support during anesthesia. Additionally, our findings suggest that diastolic function, as expressed by the E/e' ratio, does not worsen during anesthesia.

Systemic Oxygen Delivery during One-Lung Ventilation: Comparison between Propofol and Sevoflurane Anaesthesia in a Randomised Controlled Trial

Systemic oxygen delivery (DO₂) is a more comprehensive marker of patient status than arterial oxygen saturation (SaO₂), and DO₂ in the range of 330–500 mL min⁻¹ is reportedly adequate during anaesthesia. We measured DO₂ during one-lung ventilation (OLV) for thoracic surgery—where the risk of pulmonary shunt is significant, and hypoxia occurs frequently—and compared sevoflurane and propofol, the two most commonly used anaesthetics in terms of DO₂. Sevoflurane impairs hypoxic pulmonary vasoconstriction. Thus, our hypothesis was that propofol-based anaesthesia would show a higher DO₂ value than sevoflurane-based anaesthesia. This was a double-blinded randomised controlled trial conducted at a university hospital from 2017 to 2018. The study population consisted of patients scheduled for lobectomy under OLV (N = 120). Sevoflurane or propofol was titrated to a bispectral index of 40–50. Haemodynamic variables were measured during two-lung ventilation (TLV) and OLV at 15 and 45 min (OLV15 and OLV45, respectively) using oesophageal Doppler monitoring. The mean DO₂ (mL min⁻¹) was not different between the sevoflurane and propofol anaesthesia groups (TLV: 680 vs. 706; OLV15: 685 vs. 703; OLV45: 759 vs. 782, respectively). SaO₂ was not correlated with DO₂ (r = 0.09, p = 0.100). Patients with SaO₂ < 94% showed adequate DO₂ (641 ± 203 mL min⁻¹), and patients with high SaO₂ (> 97%) showed inadequate DO₂ (14% of measurements < 500 mL min⁻¹). In conclusion, DO₂ did not significantly differ between sevoflurane and propofol. SaO₂ was not correlated with DO₂ and was not informative regarding whether the patients were receiving an adequate oxygen supply. DO₂ may provide additional information on patient status, which may be especially important when patients show a low SaO₂.

Pharmacodynamic Analysis of the Influence of Propofol on Left Ventricular Long-Axis Systolic Performance in Cardiac Surgical Patients

BACKGROUND

Propofol induced a decline in the left ventricular (LV) systolic performance in non-cardiac surgery. We tested the hypothesis that propofol decreased the LV contractile function by dose dependent manner in cardiac surgery patients.

METHODS

Anesthesia was maintained with target-controlled infusions of propofol and remifentanil in cardiac surgery patients. With a fixed effect-site concentration (Ce) of remifentanil (20 ng/mL) after sternotomy, the Ce of propofol was adjusted to maintain a Bispectral index of 40-60 (Ce1). Mitral annular Doppler tissue image tracings and other echocardiographic variables, including end-diastolic and end-systolic volumes, stroke volume, and mitral inflow pulse wave Doppler profile at Ce1, were recorded using transesophageal echocardiography. Echocardiographic recordings were repeated after the Ce-values of propofol were doubled and tripled at 10-minute intervals (defined as Ce2 and Ce3, respectively). Serial changes in echocardiographic variables for each Ce of propofol were assessed using generalized linear mixed effect modeling. The pharmacodynamic relationship between the Ce of propofol and peak systolic mitral annular velocity (Sm) was analyzed by logistic regression using non-linear mixed effect modeling (NONMEM).

RESULTS

Means of Ce1, Ce2, and Ce3 were 0.8, 1.6, and 2.4 μg/mL, respectively, and their means of Sm (95% confidence interval) were 9.7 (9.3-10.2), 8.7 (8.2-9.1), and 7.5 cm/sec (7.0-8.0), respectively (P < 0.01). Ce values of propofol and Sm showed a significant inter-correlation and predictability (intercept, 10.8; slope-1.0 in generalized mixed linear modeling; P < 0.01). Ce values producing 10% and 20% decline of Sm with 50%-probability were 1.4 and 2.1 μ/mL, respectively.

CONCLUSION

Propofol reduces LV systolic long-axis performance in a dose-dependent manner.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01826149.

Intraoperative Secondary Insults During Orthopedic Surgery in Traumatic Brain Injury

BACKGROUND

Secondary insults worsen outcomes after traumatic brain injury (TBI). However, data on intraoperative secondary insults are sparse. The primary aim of this study was to examine the prevalence of intraoperative secondary insults during orthopedic surgery after moderate-severe TBI. We also examined the impact of intraoperative secondary insults on postoperative head computed tomographic scan, intracranial pressure (ICP), and escalation of care within 24 hours of surgery.

MATERIALS AND METHODS

We reviewed medical records of TBI patients 18 years and above with Glasgow Coma Scale score <13 who underwent single orthopedic surgery within 2 weeks of TBI. Secondary insults examined were: systemic hypotension (systolic blood pressure<90 mm Hg), intracranial hypertension (ICP>20 mm Hg), cerebral hypotension (cerebral perfusion pressure<50 mm Hg), hypercarbia (end-tidal CO2>40 mm Hg), hypocarbia (end-tidal CO2<30 mm Hg in absence of intracranial hypertension), hyperglycemia (glucose>200 mg/dL), hypoglycemia (glucose<60 mg/dL), and hyperthermia (temperature >38°C).

RESULTS

A total of 78 patients (41 [18 to 81] y, 68% male) met the inclusion criteria. The most common intraoperative secondary insults were systemic hypotension (60%), intracranial hypertension and cerebral hypotension (50% and 45%, respectively, in patients with ICP monitoring), hypercarbia (32%), and hypocarbia (29%). Intraoperative secondary insults were associated with worsening of head computed tomography, postoperative decrease of Glasgow Coma Scale score by ≥2, and escalation of care. After Bonferroni correction, association between cerebral hypotension and postoperative escalation of care remained significant (P<0.001).

CONCLUSIONS

Intraoperative secondary insults were common during orthopedic surgery in patients with TBI and were associated with postoperative escalation of care. Strategies to minimize intraoperative secondary insults are needed.

Assessment of Left Ventricular Dimensions by Transoesophageal Echocardiography in Patients During Coronary Artery Bypass Surgery

OBJECTIVE

Normative values of left ventricular (LV) end-diastolic area and diameter (EDA and EDD) for intraoperative transoesophageal echocardiography (TEE) have not been established. We aimed to define the ranges of LV EDA and EDD for intraoperative TEE examinations in patients undergoing coronary artery bypass graft (CABG) surgery.

METHODS

A MEDLINE search for studies reporting LV EDA and EDD in CABG patients was performed. Individual-level dataset from 333 anaesthetised and mechanically ventilated patients with preserved LV function (study population) were received from 8 studies. EDA and calculated EDD values in the study population were compared with summary mean EDD values obtained by transthoracic echocardiography (TTE) in 2 studies of 500 awake patients with coronary artery disease (CAD). Further, the influence of prespecified factors on EDD was evaluated through a multivariate regression model.

RESULTS

LV EDA and EDD values measured by TEE in anaesthetised CABG patients were 16.7±4.7 cm2 and 4.6±0.6 cm, respectively. EDD values measured by TEE in anaesthetised patients were 10% to 13% less those measured by TTE in 2 studies of awake patients (p<0.001). Body surface area, age and fractional area change but not sex were factors that affected LV EDD.

CONCLUSION

LV EDD values measured by intraoperative TEE in anaesthetised and mechanically ventilated CABG patients were 10% to 13% less than those measured by TTE in awake CAD patients. This finding indicates that independent normative values specific for intraoperative TEE should be established for guiding intraoperative clinical decisions.

Early Systolic Dysfunction Following Traumatic Brain Injury: A Cohort Study

OBJECTIVE

Prior studies have suggested that traumatic brain injury may affect cardiac function. Our study aims were to determine the frequency, longitudinal course, and admission risk factors for systolic dysfunction in patients with moderate-severe traumatic brain injury.

DESIGN

Prospective cohort study.

SETTING

Level 1 trauma center.

MEASUREMENTS

Transthoracic echocardiogram within 1 day and over the first week after moderate-severe traumatic brain injury; transthoracic echocardiogram within 1 day after mild traumatic brain injury (comparison group).

MEASUREMENTS AND MAIN RESULTS

Systolic function was assessed by transthoracic echocardiogram, and systolic dysfunction was defined as fractional shortening less than 25%. Multivariable Poisson regression models examined admission risk factors for systolic dysfunction. Systolic function in 32 patients with isolated moderate-severe traumatic brain injury and 32 patients with isolated mild traumatic brain injury (comparison group) was assessed with transthoracic echocardiogram. Seven (22%) moderate-severe traumatic brain injury and 0 (0%) mild traumatic brain injury patients had systolic dysfunction within the first day after injury (p < 0.01). All patients with early systolic dysfunction recovered in 1 week. Younger age (relative risk, 0.87; 95% CI, 0.79-0.94; for 1 yr increase in age) and lower admission Glasgow Coma Scale score (relative risk, 0.34; 95% CI, 0.20-0.58; for one unit increase in Glasgow Coma Scale) were independently associated with the development of systolic dysfunction among moderate-severe traumatic brain injury patients.

CONCLUSIONS

Early systolic dysfunction can occur in previously healthy patients with moderate-severe traumatic brain injury, and it is reversible over the first week of hospitalization. Younger age and lower admission Glasgow Coma Scale score are independently associated with the development of systolic dysfunction after moderate-severe traumatic brain injury.

The Effects of Dexmedetomidine on Myocardial Function Assessed by Tissue Doppler Echocardiography During General Anesthesia in Patients With Diastolic Dysfunction: A CONSORT-Prospective, Randomized, Controlled Trial

Dexmedetomidine is a commonly used sedative and adjuvant agent to general anesthesia. The present was designed to evaluate the effects of dexmedetomidine on myocardial function by using tissue Doppler echocardiography during general anesthesia in patients with diastolic dysfunction.Forty patients undergoing orthostatic surgery with ejection fraction preserved diastolic dysfunction grade 2 or 3 were randomly allocated to the Control and Dex group (n = 20, each). In the Dex group, dexmedetomidine was given as an initial loading dose of 1.0 μg/kg over 10 minutes followed by a maintenance dose of 0.5 μg/kg/h. The ratio of peak early diastolic transmitral or transtricuspid inflow velocity to early diastolic mitral or tricuspid annular velocity (LV or RV E/e') and left or right ventricular myocardial performance index (LV or RV MPI) were measured at before and after the administration dexmedetomidine or saline.The Dex group showed significant decrease of heart rate (P = 0.038), and increase of mean blood pressure (P < 0.001), LV E/e' (P = 0.025), and LV MPI (P < 0.001) compared to those of the Control group on a linear mixed model analysis. Also, the Dex group showed significant increase of RV E/e' (P < 0.001) and RV MPI (P = 0.028) compared to those of the Control group.Intraoperative dexmedetomidine administration during general anesthesia was appeared to deteriorate biventricular function in patients with diastolic dysfunction. We suggest careful consideration and a need for reducing dosage when administrating dexmedetomidine in patients with diastolic dysfunction.

Modern inhalational anesthetics for refractory status epilepticus

BACKGROUND

Our goal was to perform a systematic review of the literature on the use of modern inhalational anesthetic agents for refractory status epilepticus and their impact on seizure control.

METHODS

All articles from MEDLINE, BIOSIS, EMBASE, Global Health, HealthStar, Scopus, Cochrane Library, the International Clinical Trials Registry Platform (inception to March 2014), reference lists of relevant articles, and gray literature were searched. The strength of evidence was adjudicated using both the Oxford and Grading of Recommendation Assessment Development and Education methodology by two independent reviewers.

RESULTS

Overall, 19 studies were identified, with 16 manuscripts and 3 meeting abstracts. A total of 46 patients were treated. Adult (n=28) and pediatric patients (n=18) displayed 92.9% and 94.4% seizure control with treatment, respectively. Isoflurane was used in the majority of cases. Hypotension was the only complication described.

CONCLUSIONS

Oxford level 4, Grading of Recommendation Assessment Development and Education D evidence exists to support the use of isoflurane in refractory status epilepticus to obtain burst suppression. Insufficient data exist to comment on the efficacy of desflurane and xenon at this time.

Effects of elevated artificial pneumoperitoneum pressure on invasive blood pressure and levels of blood gases

BACKGROUND AND OBJECTIVE

to evaluate the clinical, hemodynamic, gas analysis and metabolic repercussions of high transient pressures of pneumoperitoneum for a short period of time to ensure greater security for introduction of the first trocar.

METHODS

sixty-seven patients undergoing laparoscopic procedures were studied and randomly distributed in P12 group: n=30 (intraperitoneal pressure [IPP] 12mmHg) and P20 group: n=37 (IPP of 20mmHg). Mean arterial pressure (MAP) was evaluated by catheterization of the radial artery; and through gas analysis, pH, partial pressure of oxygen (PaO2), partial pressure of CO2 (PaCO2), bicarbonate (HCO3) and alkalinity (BE) were evaluated. These parameters were measured in both groups at time zero before pneumoperitoneum (TP0); at time 1 (TP1) when IPP reaches 12mmHg in both groups; at time 2 (TP2) after five min with IPP=12mmHg in P12 and after 5min with IPP=20mmHg at P20; and at time 3 (TP3) after 10min with IPP=12mmHg in P12 and with return of IPP from 20 to 12mmHg, starting 10min after TP1 in P20. Different values from those considered normal for all parameters assessed, or the appearance of atypical organic phenomena, were considered as clinical changes.

RESULTS

there were statistically significant differences in P20 group in MAP, pH, HCO3 and BE, but within normal limits. No clinical and pathological changes were observed.

CONCLUSIONS

high and transient intra-abdominal pressure causes changes in MAP, pH, HCO3 and BE, but without any clinical impact on the patient.

Effects of elevated artificial pneumoperitoneum pressure on invasive blood pressure and levels of blood gases

BACKGROUND AND OBJECTIVE

to evaluate the clinical, hemodynamic, gas analysis and metabolic repercussions of high transient pressures of pneumoperitoneum for a short period of time to ensure greater security for introduction of the first trocar.

METHODS

sixty-seven patients undergoing laparoscopic procedures were studied and randomly distributed in P12 group: n=30 (intraperitoneal pressure [IPP] 12mmHg) and P20 group: n=37 (IPP of 20mmHg). Mean arterial pressure (MAP) was evaluated by catheterization of the radial artery; and through gas analysis, pH, partial pressure of oxygen (PaO2), partial pressure of CO2 (PaCO2), bicarbonate (HCO3) and alkalinity (BE) were evaluated. These parameters were measured in both groups at time zero before pneumoperitoneum (TP0); at time 1 (TP1) when IPP reaches 12mmHg in both groups; at time 2 (TP2) after five min with IPP=12mmHg in P12 and after 5min with IPP=20mmHg at P20; and at time 3 (TP3) after 10min with IPP=12mmHg in P12 and with return of IPP from 20 to 12mmHg, starting 10min after TP1 in P20. Different values from those considered normal for all parameters assessed, or the appearance of atypical organic phenomena, were considered as clinical changes.

RESULTS

there were statistically significant differences in P20 group in MAP, pH, HCO3 and BE, but within normal limits. No clinical and pathological changes were observed.

CONCLUSIONS

high and transient intra-abdominal pressure causes changes in MAP, pH, HCO3 and BE, but without any clinical impact on the patient.

Anaesthetic perioperative management of patients with pancreatic cancer

Pancreatic cancer remains a significant and unresolved therapeutic challenge. Currently, the only curative treatment for pancreatic cancer is surgical resection. Pancreatic surgery represents a technically demanding major abdominal procedure that can occasionally lead to a number of pathophysiological alterations resulting in increased morbidity and mortality. Systemic, rather than surgical complications, cause the majority of deaths. Because patients are increasingly referred to surgery with at advanced ages and because pancreatic surgery is extremely complex, anaesthesiologists and surgeons play a crucial role in preoperative evaluations and diagnoses for surgical intervention. The anaesthetist plays a key role in perioperative management and can significantly influence patient outcome. To optimise overall care, patients should be appropriately referred to tertiary centres, where multidisciplinary teams (surgical, medical, radiation oncologists, gastroenterologists, interventional radiologists and anaesthetists) work together and where close cooperation between surgeons and anaesthesiologists promotes the safe performance of major gastrointestinal surgeries with acceptable morbidity and mortality rates. In this review, we sought to provide simple daily recommendations to the clinicians who manage pancreatic surgery patients to make their work easier and suggest a joint approach between surgeons and anaesthesiologists in daily decision making.

Myocardial dysfunction in acute traumatic brain injury relieved by surgical decompression

Traumatic brain injury (TBI) is a major public health issue and is a leading cause of death in North America. After a primary TBI, secondary brain insults can predispose patients to a worse outcome. One of the earliest secondary insults encountered during the perioperative period is hypotension, which has been directly linked to both mortality and poor disposition after TBI. Despite this, it has been shown that hypotension commonly occurs during surgery for TBI. We present a case of intraoperative hypotension during surgery for TBI, where the use of transthoracic echocardiography had significant diagnostic and therapeutic implications for the management of our patient. We then discuss the issue of cardiac dysfunction after brain injury and the implications that echocardiography may have in the management of this vulnerable patient population.

Impact of propofol anesthesia induction on cardiac function in low-risk patients as measured by intraoperative Doppler tissue imaging

BACKGROUND

Despite a few experimental studies showing a dose-dependent myocardial depressive effect of propofol anesthesia induction, few clinical data are available to determine its precise impact on myocardial function, probably because of its brevity and a lack of appropriate evaluation tools. The purpose of this study was to examine the impact of propofol-based anesthesia induction on left ventricular (LV) function using Doppler tissue and speckle-tracking imaging.

METHODS

In 19 low-risk patients with normal LV systolic and diastolic function undergoing noncardiac surgery (all women; mean age, 42 years), propofol bolus (2.0 mg/kg) was administered intravenously for anesthesia induction. LV ejection fraction, global peak systolic longitudinal strain, and tissue Doppler-derived indices of mitral annular velocity during systole (S'), early diastole (e'), and atrial contraction (a') were determined by intraoperative transthoracic echocardiography before and 1, 3, and 5 min after propofol bolus (T0, T1, T2, and T3, respectively).

RESULTS

The following at T1, T2, and T3 were significantly less in magnitude than at T0: septal S' (5.61, 5.61, and 5.51 vs 7.60 cm/sec, P < .001), lateral S' (5.75, 5.89, and 5.94 vs 8.12 cm/sec, P < .001), septal e' (10.10, 10.26, and 10.07 vs 11.4 cm/sec, P < .01), septal a' (6.70, 6.21, and 6.13 vs 8.58 cm/sec, P < .01), lateral a' (7.29, 6.81, and 6.85 vs 9.01 cm/sec, P < .01), and longitudinal strain (-19.36%, -19.71%, and -19.61% vs -22.28%, P < .001). LV ejection fraction was not significantly changed (P = .361).

CONCLUSIONS

Propofol anesthesia induction diminished LV and atrial contraction in low-risk patients with prior normal LV function. Further studies are needed to understand the clinical implications, particularly for higher risk populations.

Prevalence and risk factors for intraoperative hypotension during craniotomy for traumatic brain injury

BACKGROUND

Hypotension after traumatic brain injury (TBI) is associated with poor outcomes. However, data on intraoperative hypotension (IH) are scarce and the effect of anesthetic agents on IH is unknown. We examined the prevalence and risk factors for IH, including the effect of anesthetic agents during emergent craniotomy for isolated TBI.

METHODS

This is a retrospective cohort study of patients 18 years and above, who underwent emergent craniotomy for TBI at Harborview Medical Center (level 1 trauma center) between October 2007 and January 2010. Demographic, clinical, and radiographic characteristics and hemodynamic and anesthetic data were abstracted from medical and electronic anesthesia records. Hypotension was defined as systolic blood pressure <90 mm Hg. Univariate analyses were performed to compare the clinical characteristics of patients with and without IH, and multiple logistic regression analysis was used to determine independent risk factors for IH.

RESULTS

Data abstracted from 113 eligible patients aged 48±19 years were analyzed. IH was common (n=73, 65%) but not affected by the choice of anesthetic agent. Independent risk factors for IH were multiple computed tomographic (CT) lesions [adjusted odds ratios (AOR) 19.1; 95% confidence interval (CI), 2.08-175.99; P=0.009], subdural hematoma (AOR 17.9; 95% CI, 2.97-108.10; P=0.002), maximum CT lesion thickness (AOR 1.1; 95% CI, 1.01-1.13; P=0.016), and anesthesia duration (AOR 1.1; 95% CI, 1.01-1.30; P=0.009).

CONCLUSIONS

IH was common in adult patients with isolated TBI undergoing emergent craniotomy. The presence of multiple CT lesions, subdural hematoma, maximum thickness of CT lesion, and longer duration of anesthesia increase the risk for IH.

Diastolic dysfunction and heart failure with a preserved ejection fraction: Relevance in critical illness and anaesthesia

Epidemiological and clinical studies suggest that HF with a preserved ejection fraction will become the more common form of HF which clinicians will encounter. The spectrum of diastolic disease extends from the asymptomatic phase to fulminant cardiac failure. These patients are commonly encountered in operating rooms and critical care units. A clearer understanding of the underlying pathophysiology and clinical implications of HF with a preserved ejection fraction is fundamental to directing further research and to evaluate interventions. This review highlights the impact of diastolic dysfunction and HF with a preserved ejection fraction during the perioperative period and during critical illness.

Perioperative assessment of diastolic dysfunction

Assessment of diastolic function should be a component of a comprehensive perioperative transesophageal echocardiographic examination. Abnormal diastolic function exists in >50% of patients presenting for cardiac and high-risk noncardiac surgery, and has been shown to be an independent predictor of adverse postoperative outcome. Normalcy of systolic function in 50% of patients with congestive heart failure implicates diastolic dysfunction as the probable etiology. Comprehensive evaluation of diastolic function requires the use of various, load-dependent Doppler techniques This is further complicated by the additional effects of dehydration and anesthetic drugs on myocardial relaxation and compliance as assessed by these Doppler measures. The availability of more sophisticated Doppler techniques, e.g., Doppler tissue imaging and flow propagation velocity, makes it possible to interrogate left ventricular diastolic function with greater precision, analyze specific stages of diastole, and to differentiate abnormalities of relaxation from compliance. Additionally, various Doppler-derived ratios can be used to estimate left ventricular filling pressures. The varying hemodynamic environment of the operating room mandates modification of the diagnostic algorithms used for ambulatory cardiac patients when left ventricular diastolic function is evaluated with transesophageal echocardiography in anesthetized surgical patients.

Desflurane and Sevoflurane in Cardiac Surgery: A Meta-Analysis of Randomized Clinical Trials

OBJECTIVES

The authors performed a meta-analysis to investigate whether the cardioprotective effects of volatile anesthetics translate into decreased morbidity and mortality in patients undergoing cardiac surgery.

BACKGROUND

It is commonly believed that the choice of the primary anesthetic agent does not result in different outcomes after cardiac surgery. Recent evidence, however, has indicated that volatile anesthetics improve postischemic recovery at a cellular level, in isolated hearts, in animals, and in humans.

METHODS

Four investigators independently searched BioMedCentral and PubMed. Inclusion criteria were random allocation to treatment and comparison of a total intravenous anesthesia regimen versus an anesthesia plan including desflurane or sevoflurane performed on cardiosurgical patients. Exclusion criteria were duplicate publications, nonhuman experimental studies, and no outcome data. The endpoints were the rate of perioperative myocardial infarction and hospital mortality.

RESULTS

The search yielded 22 studies, involving 1,922 patients. Volatile anesthetics were associated with significant reductions of myocardial infarctions (24/979 [2.4%] in the volatile anesthetics group v 45/874 [5.1%] in the control arm, odds ratio [OR] = 0.51 [0.32-0.84], p for effect = 0.008, and p for heterogeneity = 0.77) and mortality (4/977 [0.4%] v 14/872 [1.6%], OR = 0.31 [0.12-0.80], p for effect = 0.02, and p for heterogeneity = 0.88).

CONCLUSIONS

Desflurane and sevoflurane have cardioprotective effects that result in decreased morbidity and mortality. The present data show for the first time that the choice of an anesthetic regimen based on administration of halogenated anesthetics is associated with a better outcome after cardiac surgery.

Respiratory and haemodynamic effects of volume-controlled vs pressure-controlled ventilation during laparoscopy: a cross-over study with echocardiographic assessment

BACKGROUND

The effects of pressure-controlled (PC) ventilation on the ventilatory and haemodynamic parameters during laparoscopy procedures had not been carefully assessed. This prospective cross-over study was undertaken to compare how volume-controlled (VC) and PC modes could affect pulmonary mechanics, gas exchange, and cardiac function in patients undergoing laparoscopy.

METHODS

Twenty-one patients undergoing laparoscopic urological procedures had their lungs ventilated at the beginning with VC ventilation. PC ventilation was instituted at the end of the VC sequence. Ventilator settings were adjusted to keep tidal volume, respiratory rate, and Fi(o(2)) constant in every mode. A complete set of ventilatory, haemodynamic, and gas exchange parameters was obtained under VC after 40 min of pneumoperitoneum and 20 min after switching for PC. Transoesophageal echocardiography was performed in order to evaluate systolic and diastolic function of the heart.

RESULTS

When VC was switched to PC, peak airway pressure decreased [mean (sd) 32 (6) vs 27 (6) cm H(2)O; P < 0.0001], peak inspiratory flow increased [17 (3) vs 48 (8) litre min(-1); P < 0.0001), and dynamic compliance improved [+15 (8)%]. No difference was noted for static airway pressure, static compliance, and arterial oxygenation. No significant change could be demonstrated in the systolic [left ventricular end-systolic wall stress 66 (16) vs 63 (14) x 10(3) dyn cm(-2) m(-2)] or diastolic function [early diastolic velocity 10.3 (2.5) vs 10.5 (2.7) cm s(-1)].

CONCLUSIONS

In this study, no short-term beneficial effect of PC ventilation could be demonstrated over conventional VC ventilation in patients with pneumoperitoneum.

Intra-operative myocardial ischaemia cannot be detected by analysis of transmitral inflow patterns in patients undergoing off-pump coronary surgery

BACKGROUND AND OBJECTIVE

Transmitral inflow patterns have been used for detection of myocardial ischaemia. However, its diagnostic value has not been tested in anaesthetized and mechanically ventilated patients undergoing coronary artery bypass graft surgery.

METHODS

Transmitral inflow patterns were studied by transoesophageal Doppler echocardiography in 43 patients undergoing coronary artery bypass graft surgery without cardiopulmonary bypass after opening of the sternum (baseline) and during grafting of the left anterior descending artery. Peak early (E) and peak late (A) transmitral velocities and their ratio (E/A) were recorded. Myocardial ischaemia was defined by standard criteria using two-dimensional echocardiography and seven-lead electrocardiogram.

RESULTS

Thirty-one patients (64 +/- 8 yr, 9 women) fulfilled the predefined inclusion criteria for analysis. During distal revascularization, 16 patients showed myocardial ischaemia and 15 did not. The use of vasoactive drugs, haemodynamic findings and transmitral inflow patterns were similar in both groups at baseline and during grafting. In the ischaemic group, E was 67.1 +/- 13.9 cm s-1 at baseline and 69.5 +/- 23.2 cm s-1 during grafting, and the E/A ratios were 1.3 +/- 0.3 and 1.4 +/- 0.9, respectively. In the non-ischaemic group, E was 64.0 +/- 17.1 cm s-1 at baseline and 60.9 +/- 14.8 cm s-1 during grafting, and the E/A ratios were 1.4 +/- 0.7 and 1.2 +/- 0.3, respectively.

CONCLUSIONS

Analysis of Doppler findings of transmitral inflow patterns did not allow for detection of myocardial ischaemia during surgical revascularization of the myocardium.

Diastolic heart failure in anaesthesia and critical care

Diastolic heart failure is an underestimated pathology with a high risk of acute decompensation during the perioperative period. This article reviews the epidemiology, risk factors, pathophysiology, and treatment of diastolic heart failure. Although frequently underestimated, diastolic heart failure is a common pathology. Diastolic heart failure involves heart failure with preserved left ventricular (LV) function, and LV diastolic dysfunction may account for acute heart failure occurring in critical care situations. Hypertensive crisis, sepsis, and myocardial ischaemia are frequently associated with acute diastolic heart failure. Symptomatic treatment focuses on the reduction in pulmonary congestion and the improvement in LV filling. Specific treatment is actually lacking, but encouraging data are emerging concerning the use of renin-angiotensin-aldosterone axis blockers, nitric oxide donors, or, very recently, new agents specifically targeting actin-myosin cross-bridges.

Effects of sevoflurane and propofol on left ventricular diastolic function in patients with pre-existing diastolic dysfunction

BACKGROUND

The effects of anaesthetics on left ventricular (LV) diastolic function in patients with pre-existing diastolic dysfunction are not well known. We hypothesized that propofol but not sevoflurane will worsen the pre-existing LV diastolic dysfunction.

METHODS

Of 24 randomized patients, 23 fulfilled the predefined echocardiographic criterion for diastolic dysfunction. They received general anaesthesia with sevoflurane 1 MAC (n=12) or propofol 4 mug ml(-1) (n=11). Echocardiographic examinations were performed at baseline and in anaesthetized patients under spontaneous breathing and under positive pressure ventilation. Analysis focused on peak early diastolic velocity of the mitral annulus (E(a)).

RESULTS

During spontaneous breathing, E(a) was higher in the sevoflurane than in the propofol group [mean (95% CI) 7.0 (5.9-8.1) vs 5.5 (4.7-6.3) cm s(-1); P<0.05], reflecting an increase of E(a) from baseline only in the sevoflurane group (P<0.01). Haemodynamic findings were similar in both groups, but the end-tidal carbon dioxide content was more elevated in the propofol group (P<0.01). During positive pressure ventilation, E(a) was similarly low in the sevoflurane and propofol groups [5.3 (4.2-6.3) and 4.4 (3.6-5.2) cm s(-1), respectively].

CONCLUSIONS

During spontaneous breathing, early diastolic function improved in the sevoflurane but not in the propofol group. However, during positive pressure ventilation and balanced anaesthesia, there was no evidence of different effects caused by the two anaesthetics.

Inhalational or intravenous anesthetics for craniotomies? Pro inhalational

PURPOSE OF REVIEW

In neurosurgery, anesthesiologists and surgeons focus on the same target - the brain. The nature of anesthetics is to interact with brain physiology, leading to favorable and adverse effects. Research in neuroanesthesia over the last three decades has been dedicated to identifying the optimal anesthetic agent to maintain coupling between cerebral blood flow and metabolism, keep cerebrovascular autoregulation intact, and not increase cerebral blood volume and intracranial pressure.

RECENT FINDINGS

Sevoflurane is less vasoactive than halothane, enflurane, isoflurane, or desflurane. The context sensitive half-life is short and similar to that of desflurane, which translates into fast on and offset. Compared with propofol, sevoflurane decreases cerebral blood flow to a lesser extent, while cerebral metabolism is suppressed to the same degree. Sevoflurane does not increase intracranial pressure, while propofol decreases intracranial pressure.

SUMMARY

In neurosurgical patients with normal intracranial pressure, sevoflurane might be a good alternative to propofol. In patients with reduced intracranial elastance, caused by space occupying lesions, with elevated intracranial pressure or complex surgical approaches, propofol should remain first choice.

Anesthesia for the elderly: selected topics

PURPOSE OF REVIEW

With the graying of the Western population, there is a continuous increase in the proportion of elderly patients undergoing surgical procedures. Geriatric anesthesia is emerging from a 'subspecialty' to the mainstream of today's anesthesia and perioperative care. Much has been written on anesthesia for the elderly, but this review will concentrate on selected topics related to elderly care that represent current unresolved and pertinent issues for the care of the elderly surgical patient.

RECENT FINDINGS

Postoperative cognitive dysfunction, cardiac diastolic dysfunction and prophylactic perioperative beta-blockade in the process of major noncardiac surgery are three main topics that have recently attracted great interest in clinical practice and research, and have therefore been chosen as the selected topics for this current review.

SUMMARY

Although age is a clear risk factor for postoperative cognitive dysfunction, the association of general anesthesia with cognitive dysfunction is less clear, as is the effect of anesthesia per se or surgery on long-term cognitive dysfunction. Cardiac diastolic dysfunction is a relatively new and evolving concept in anesthesia and perioperative medicine, yet clearly diastolic dysfunction even with a normal ejection fraction may have a significant effect on the perioperative outcome and management of elderly patients. Small, but powerful studies have shown significant outcome benefit with prophylactic perioperative beta-blockade in high-risk patients undergoing major noncardiac surgery. Data from other studies, however, are still conflicting and the final verdict awaits larger scale outcome studies.