Cardiovascular effects of mechanical ventilation and weaning

Analysis of short-term ventilation weaning for patients in spontaneous supratentorial intracranial hemorrhage

Prolonged ventilation is a complication of spontaneous supratentorial hemorrhage patients, but the predictive relationship with successful weaning in this patient cohort is not understood. Here, we evaluate the incidence and factors of ventilation weaning in case of spontaneous supratentorial hemorrhage. We retrospectively studied data from 166 patients in the same hospital from January 2015 to March 2021 and analyzed factors for ventilation weaning. The clinical data recorded included patient age, gender, timing of operation, initial Glasgow Coma Scale (GCS), Intracranial hemorrhage (ICH) score, alcohol drinking, cigarette smoking, medical comorbidity, and the blood data. Predictors of patient outcomes were determined by the Student t test, chi-square test, and logistic regression. We recruited and followed 166 patients who received operation for spontaneous supratentorial hemorrhage with cerebral herniation. The group of successful weaning had 84 patients and the group of weaning failed had 82 patients. The patient's age, type of operation, GCS on admission to the Intensive care unit (ICU), GCS at discharge from the ICU, medical comorbidity was significantly associated with successful weaning, according to Student t test and the chi-square test. According to our findings, patients with stereotaxic surgery, less history of cardiovascular or prior cerebral infarction, GCS >8 before admission to the hospital for craniotomy, and a blood albumin value >3.5 g/dL have a higher chance of being successfully weaned off the ventilator within 14 days.

Comparison of neurally adjusted ventilatory assist and synchronized intermittent mandatory ventilation in preterm infants after patent ductus arteriosus ligation: a retrospective study

OBJECTIVE

This study aimed to compare the efficacy of neurally adjusted ventilatory assist (NAVA) to synchronized intermittent mandatory ventilation (SIMV) in preterm infants requiring mechanical ventilation after patent ductus arteriosus (PDA) ligation.

METHODS

A retrospective analysis was conducted on intubated preterm infants who underwent PDA ligation at our hospital from July 2021 to January 2023. Infants were divided into NAVA or SIMV groups based on the ventilation mode after surgery.

RESULTS

Fifty preterm infants were included. During treatment, peak inspiratory pressure (PIP) and mean airway pressure (MAP) were lower with NAVA compared to SIMV (PIP: 19.1 ± 2.9 vs. 22.4 ± 3.6 cmH2O, P < 0.001; MAP: 9.1 ± 1.8 vs. 10.9 ± 2.7 cmH2O, P = 0.002). PaO2 and PaO2/FiO2 were higher with NAVA (PaO2: 94.0 ± 11.7 vs. 84.8 ± 15.8 mmHg, P = 0.031; PaO2/FiO2: 267 [220-322] vs. 232 [186-290] mmHg, P = 0.025). Less sedation was required with NAVA (midazolam: 1.5 ± 0.5 vs. 1.1 ± 0.3 μg/kg/min, P < 0.001).

CONCLUSION

Compared to SIMV, early use of NAVA post PDA ligation in preterm infants was associated with decreased PIP and MAP. Early NAVA was also associated with reduced sedation needs and improved oxygenation. However, further studies are warranted to quantify the benefits of NAVA ventilation.

Difficult Respiratory Weaning after Cardiac Surgery: A Narrative Review

Respiratory weaning after cardiac surgery can be difficult or prolonged in up to 22.7% of patients. The inability to wean from a ventilator within the first 48 h after surgery is related to increased short- and long-term morbidity and mortality. Risk factors are mainly non-modifiable and include preoperative renal failure, New York Heart Association, and Canadian Cardiac Society classes as well as surgery and cardio-pulmonary bypass time. The positive effects of pressure ventilation on the cardiovascular system progressively fade during the progression of weaning, possibly leading to pulmonary oedema and failure of spontaneous breathing trials. To prevent this scenario, some parameters such as pulmonary artery occlusion pressure, echography-assessed diastolic function, brain-derived natriuretic peptide, and extravascular lung water can be monitored during weaning to early detect hemodynamic decompensation. Tracheostomy is considered for patients with difficult and prolonged weaning. In such cases, optimal patient selection, timing, and technique may be important to try to reduce morbidity and mortality in this high-risk population.

Mechanical ventilation strategies alter cardiovascular biomarkers in an infant rat model

Mechanical ventilation (MV) is routinely used in pediatric general anesthesia and critical care, but may adversely affect the cardiocirculatory system. Biomarkers are increasingly measured to assess cardiovascular status and improve clinical treatment decision-making. As the impact of mechanical ventilation strategies on cardiovascular biomarkers in ventilated infants is largely unknown, we conducted this retrospective study in a healthy in vivo infant rat ventilation model using 14-days old Wistar rats. We hypothesized that 2 h of mechanical ventilation with high and low positive end-expiratory pressure (PEEP), hyperoxemia, hypoxemia, hypercapnia, and hypocapnia would significantly impact B-type natriuretic peptide (BNP), vascular endothelial growth factor (VEGF), and endothelin-1 (ET-1). We found BNP to be driven by both high (9 cmH₂ O) and low (1 cmH₂ O) PEEP compared to ventilated control animals (P < 0.05). VEGF concentrations were associated with high PEEP, hyperoxemia, hypoxemia, and hypocapnia (P < 0.05), whereas ET-1 levels were changed only in response to hypoxemia (P < 0.05). In conclusion, the mode of mechanical ventilation alters plasma biomarker concentrations. Moreover, BNP and VEGF might serve as surrogate parameters for ventilation induced cardiovascular compromise and lung tissue damage. Furthermore, our data support the hypothesis, that sudden onset of hyperoxemia may trigger a quick VEGF release as a possible cellular survival reflex.

Effect of Troponin I Elevation on Duration of Mechanical Ventilation and Length of Intensive Care Unit Stay in Patients With Sepsis

Background

Sepsis is a leading cause of mortality and morbidity. Recent studies suggest that troponin elevation is associated with increased mortality in sepsis patients. The purpose of this study is to determine the effect of troponin elevation on mechanical ventilation duration and intensive care unit (ICU) length of stay in patients with sepsis. Additionally, we investigated the association between troponin elevation and septic shock.

Methods

The study is a retrospective observational cohort study, conducted in a community teaching hospital between October 2015 and April 2018. All adult ICU patients with sepsis who required invasive mechanical ventilation were included. Primary outcomes were mechanical ventilation duration and ICU length of stay. Secondary outcomes were hospital length of stay, in-hospital mortality and association with septic shock.

Results

A total of 125 patients were included. Troponin was elevated in 36% (45/125) of the patients. Duration of mechanical ventilation in hours was longer for troponin-positive group (troponin positive: 55.6 h vs. troponin negative: 49.6 h, 95% CI 0.001 - 0.063, P = 0.032). ICU length of stay was similar (troponin positive: 4.6 days vs. troponin negative: 4.3 days, 95% CI 0.130 - 0.270). Septic shock had higher occurrence in elevated troponin group (troponin positive: 62.2% (28/45) vs. troponin negative: 43.8% (35/80), risk ratio (RR) 1.4, P = 0.04, 95% CI 1.015 - 1.99).

Conclusions

Troponin elevation was associated with longer duration of mechanical ventilation in patients admitted to ICU with sepsis. Troponin elevation was associated with higher risk for development of septic shock. No significant effect was observed in ICU length of stay and hospital length of stay.

Management of Respiratory Failure

The management of acute respiratory failure varies according to the etiology. A clear understanding of physiology of respiration and pathophysiological mechanisms of respiratory failure is mandatory for managing these patients. The extent of abnormality in arterial blood gas values is a result of the balance between the severity of disease and the degree of compensation by cardiopulmonary system. Normal blood gases do not mean that there is an absence of disease because the homeostatic system can compensate. However, an abnormal arterial blood gas value reflects uncompensated disease that might be life threatening.

The Care-Integrated Concentration Meditation Program for Patients With Weaning Difficulty: A Pilot Study

Because of the multifaceted process of weaning patients with prolonged mechanical ventilation, enhancing weaning success remains a challenge. The Care-Integrated Concentration Meditation Program was developed on the basis of Buddhist philosophy and implemented to determine its procedural feasibility. A qualitative case study with 3 participants was conducted, and the process and initial outcomes were evaluated.

Influence of apnoeic oxygenation in respiratory and circulatory system under general anaesthesia

Apnoeic oxygenation is an alternative technique of oxygenation which is recommended in the consecutive oxygen administration with varying flows (2-10 lt/min) through a catheter which is positioned over the keel of the trachea. Apnoeic oxygenation maintains for a significant period of time the oxygenation of blood in breathless conditions. This technique was first applied in 1947 by Draper, Whitehead, and Spencer and it was studied sporadically by other inventors too. However, the international literature shows few studies that have examined closely apnoeic oxygenation and its effects on Hemodynamic image and the respiratory system of the human body. Recently they have begun to arise some studies which deal with the application of this technique in several conditions such as difficult tracheal intubation, ventilation of guinea pigs in campaign conditions where the oxygen supply is limited and calculable, the application of this technique in combination with the use of extracorporeal removal of carbon dioxide (CO2). All the above indicate, the clinical use of this technique.