Goal-directed therapy: what we know and what we need to know

A new method to evaluate carotid blood flow by continuous Doppler monitoring during cardiopulmonary resuscitation in a porcine model of cardiac arrest

AIM

We used a wearable carotid Doppler patch to study carotid blood flow patterns in a porcine model of cardiac arrest to identify return of spontaneous circulation (ROSC) and hemodynamics associated with different arrhythmias and the quality of compressions.

METHODS

Twenty Landrace pigs were used as models of cardiac arrest following a standard protocol. Carotid blood flow was monitored continuously using noninvasive ultrasound. Carotid spectral waveforms were captured during various arrhythmias and CPR. Typical carotid blood flow waveforms were recorded at the time of ROSC, and hemodynamic changes were compared with carotid blood flow parameters.

RESULTS

The results showed that the carotid blood flow waveforms varied with ventricular arrhythmia type. During CPR, compression depth correlated significantly with carotid maximal velocity (Vmax) (Spearman correlation coefficient (r) = 0.682, P < 0.001) and velocity-time integral (VTI) (r = 0.794, P < 0.001). Vmax and VTI demonstrated moderate predictive value for survival. The regular carotid blood flow pattern towards the brain was observed during ROSC, concurrent with compression waveforms. After ROSC, VTI and carotid pulse volume (cPV) showed similar trends as stroke volume (SV). The carotid minute volume (cMV) exhibited a similar trend as cardiac output (CO).

CONCLUSIONS

Carotid blood flow monitoring could provide valuable information about different arrhythmias as well as the quality of CPR. Carotid flow monitoring allows for timely and effective identification of ROSC. In addition, it may provide valuable hemodynamic information after ROSC.

Anesthesia Management for the Patient with Chronic Decompensated Heart Failure and Low Cardiac Output Undergoing CABG with Advanced Cardiac Monitoring: A Case Report

Introduction

Heart failure (HF) is a complex clinical syndrome caused by a structural or functional heart disorder. One of the most important challenges for anesthesiologists is the management of anesthesia in patients with severe heart failure, which has been facilitated by advanced monitoring systems.

Case Presentation

The patient was a 42-year-old man with a history of hypertension (HTN) and HF with involvement of the three coronary arteries (3VD) with ejection fraction (EF) 15%. He was also a candidate for elective CABG. In addition to the insertion of arterial line in the left radial artery and the Swan-Ganz catheter in the pulmonary artery, the patient was also monitored by the Edwards Lifesciences Vigilance II for cardiac index (CI) and intravenous mixed blood oxygenation (ScvO₂). Hemodynamic changes during and after surgery, as well as during inotrope infusion, were controlled, and the amount of fluid therapy was calculated by gold direct therapy (GDT) method.

Conclusions

Using PA catheter with advanced monitoring and GDT-based fluid therapy guaranteed a safe anesthesia in this patient with severe heart failure and EF < 20%. Moreover, the postoperative complications and duration of ICU stays were significantly reduced.

Perioperative trajectory of plasma viscosity: a prospective, observational, exploratory study in cardiac surgery

OBJECTIVE

Plasma viscosity is one of the critical factors that regulate microcirculatory flow but has received scant research attention. The main objective of this study was to evaluate plasma viscosity in cardiac surgery with respect to perioperative trajectory, main determinants and impact on outcome.

METHODS

Prospective, single center, observational study, including 50 adult patients undergoing cardiac surgery with cardiopulmonary bypass between 1 February 2020 - 31 May 2021. Clinical perioperative characteristics, short term outcome, standard blood analysis, plasma viscosity, total proteins and fibrinogen concentrations were recorded at ten distinct time points during the first perioperative week.

RESULTS

The longitudinal analysis showed that plasma viscosity is strongly influenced by proteins and measurement time points. Plasma viscosity showed a coefficient of variation of 11.3 +/- 1.08 for EDTA and 12.1 +/-2.1 for citrate, similarly to total proteins and hemoglobin, but significantly lower than fibrinogen (p<0.001). Plasma viscosity had lower percentage changes compared to hemoglobin (RANOVA, p<0.001), fibrinogen (RANOVA, p<0.001), and total proteins (RANOVA, p<0.001). The main determinant of plasma viscosity was protein concentrations. No association with outcome was found, but the study may have been underpowered to detect it.

CONCLUSION

Plasma viscosity had a low coefficient of variation and low perioperative changes, suggesting tight regulation. Studies linking plasma viscosity with outcome would require large patient cohorts.

Systematic preoperative tests prescription in elective surgery: it's high time to appraise!

BACKGROUND

The prescription of preoperative complementary tests aims to decrease morbidity and mortality associated to the perioperative period.

AIM

To assess the practice and the financial cost of the systematic prescription of preoperative tests.

METHODS

This was a retrospective study including all patients older than three years, scheduled for elective surgery from November 2018 to January 2019. Two attendings analyzed the data collected during the pre-anesthetic assessment and evaluated the usefulness of the ordered preoperative tests. The overall cost of prescribed preoperative tests and the cost generated by inappropriate prescriptions were also estimated.

RESULTS

This study included 1006 patients. The average age was 46.9 ± 22.05 years old. Five hundred and twenty three of them (51.98%) have no medical history. Among the planned procedures, 6.46% had an intermediate or major bleeding risk. Preoperative prescriptions were ordered by surgeons in 99% of cases. Prescriptions were justifiable in only 9.42% of cases. Abnormal findings were noted in 4.98% of the patients. The total cost was almost 80992 Dinars (≈ 24543 €). Complying the guidelines would save 70245 Dinars (≈ 21286 €) during the three months' study.

CONCLUSION

The routine prescription of preoperative complementary tests results in a significant additional economic cost. Developing national guidelines would change this attitude of unnecessary prescription.

Increased risk of hip fracture mortality associated with intraoperative hypotension in elderly hip fracture patients is related to under resuscitation

BACKGROUND

As the US and world population ages, hip fractures are increasingly more common. The mortality associated with these fractures remains high both in the immediate postoperative period and at one year. Perioperative resuscitation in this population is of key interest to prevent organ injury and mortality. Our objectives were to evaluate the effect of fluid resuscitation and hemodynamic status in the form of mean arterial pressure (MAP) on inpatient mortality of hip fracture patients.

METHODS

An institutional database was queried to compare elderly hip fracture patients that sustained in-hospital mortality to a matched control cohort. Pre-, intra-, and post-operative intravenous fluid (IVF) administration and MAP were extracted from the electronic medical record. Time from hospital presentation to the OR was also recorded.

RESULTS

1,114 total hip fractures were identified during the two-year study period, 16 of which suffered inpatient mortalities. The mortality cohort was then matched with a control of 394 hip fracture patients for the same period based on age, sex, and Charlson Comorbidity Index (CCI). Conditional logistical regression analysis found odds ratios (OR) indicating that longer time between presentation and surgery (OR per additional hour: 1.05; 95% CI: 1.01-1.08) and lower intraoperative minimum MAP (OR per 5 mmHg decrease: 0.77; 95% CI: 0.61-0.97) were associated with significantly increased odds of mortality. There was also a marginal relationship between greater intraoperative IVF administration and reduced odds of mortality (OR per 500 cc additional fluid: 0.61; 95% CI: 0.37-1.00).

CONCLUSION

Extended time from presentation to surgery and intraoperative hypotension were associated with increased likelihood of inpatient mortality in an elderly hip fracture cohort, with a possible additional effect of under-resuscitation. Further investigation into a safe intraoperative minimum MAP should be pursued.

LEVEL OF EVIDENCE

Level III.

Terms, Definitions, Nomenclature, and Routes of Fluid Administration

Fluid therapy is administered to veterinary patients in order to improve hemodynamics, replace deficits, and maintain hydration. The gradual expansion of medical knowledge and research in this field has led to a proliferation of terms related to fluid products, fluid delivery and body fluid distribution. Consistency in the use of terminology enables precise and effective communication in clinical and research settings. This article provides an alphabetical glossary of important terms and common definitions in the human and veterinary literature. It also summarizes the common routes of fluid administration in small and large animal species.

Abdominal intra-compartment syndrome - a non-hydraulic model of abdominal compartment syndrome due to post-hepatectomy hemorrhage in a man with a localized frozen abdomen due to extensive adhesions: a case report

BACKGROUND

Postoperative hemorrhage is a significant cause of morbidity and mortality following liver resection. It typically presents early within the postoperative period, and conservative management is possible in the majority of cases. We present a case of late post-hepatectomy hemorrhage associated with overt abdominal compartment syndrome resulting from a localized functional compartment within the abdomen.

CASE PRESENTATION

A 68-year-old white man was readmitted with sudden onset of upper abdominal pain, vomiting, and hemodynamic instability 8 days after an uneventful hepatic resection for metachronous colon cancer metastasis. A frozen abdomen with adhesions due to complicated previous abdominal surgeries was encountered at the first intervention, but the surgery itself and initial recovery were otherwise unremarkable. Prompt response to fluid resuscitation at admission was followed by a computed tomography of his abdomen that revealed active arterial hemorrhage in the liver resection site and hemoperitoneum (estimated volume <2 L). Selective arteriography successfully identified and embolized a small bleeding branch of his right hepatic artery. He remained hemodynamically stable, but eventually developed overt abdominal compartment syndrome. Surgical exploration confirmed a small volume of ascites and blood clots (1.2 L) under significant pressure in his supramesocolic region, restricted by his frozen lower abdomen, which we evacuated. Dramatic improvement in his ventilatory pressure was immediate. His abdomen was left open and a negative pressure device was placed for temporary abdominal closure. The fascia was formally closed after 48 hours. He was discharged home at postoperative day 6.

CONCLUSIONS

Intra-abdominal pressure and radiologic findings of intra-abdominal hemorrhage should be carefully interpreted in patients with extensive intra-abdominal adhesions. A high index of suspicion and detailed understanding of abdominal compartment mechanics are paramount for the timely diagnosis of abdominal compartment syndrome in these patients. Clinicians should be aware that abnormal anatomy (such as adhesions) coupled with localized pathophysiology (such as hemorrhage) can create a so-named abdominal intra-compartment syndrome requiring extra vigilance to diagnose.

Using cardiac output monitoring to guide perioperative haemodynamic therapy

PURPOSE OF REVIEW

The aim of this study was to review recent advances and evidence for the use of cardiac output monitors to guide perioperative haemodynamic therapy.

RECENT FINDINGS

There are multiple different cardiac output monitoring devices available for clinical use which are coupled with many different intervention protocols to manipulate perioperative haemodynamics. There is little evidence to demonstrate superiority of any one device. Previous small studies and meta-analyses have suggested that perioperative haemodynamic therapy guided by cardiac output monitoring improves outcomes after major surgery. Despite relatively low-quality evidence several national bodies have recommended 'perioperative goal-directed therapy' (GDT) as a standard of care.Recent larger trials of GDT have mostly failed to prove a benefit of GDT and one explanation for this is the increased quality of usual care that may be occurring because of initiatives such as enhanced recovery after surgery and the WHO Safer Surgery programmes.

SUMMARY

Perioperative GDT remains an exciting intervention to reduce significant morbidity following major surgery; however, it is not yet a proven standard of care. Further large pragmatic trials are required to demonstrate its effectiveness particularly in the era of enhanced recovery after surgery programmes.