Intra-Abdominal Hypertension is a Risk Factor for Increased VAP Incidence: A Prospective Cohort Study in the ICU of a Tertiary Hospital.

BACKGROUND: Ventilator-associated pneumonia (VAP) might be increased in cases with intra-abdominal hypertension (IAH). However, despite animal experimentation and physiological studies on humans in favor of this hypothesis, there is no definitive clinical data that IAH is associated with VAP. We therefore aimed to study whether IAH is a risk factor for increased incidence of VAP in critical care patients. This 1-center prospective observational cohort study was conducted in the intensive care unit of the University Hospital of Larissa, Greece, during 2013 to 2015. Consecutive patients were recruited if they presented risk factors for IAH at admission and were evaluated systematically for IAH and VAP for a 28-day period. RESULTS: Forty-five (36.6%) of 123 patients presented IAH and 45 (36.6%) presented VAP; 24 patients presented VAP following IAH. Cox regression analysis showed that VAP was independently associated with IAH (1.06 [1.01-1.11]; P = .053), while there was an indication for an independent association between VAP and abdominal surgery (1.62 [0.87-3.03]; P = .11] and chronic obstructive pulmonary disease (1.79 [0.96-3.37]; P = .06). CONCLUSIONS: Intra-abdominal hypertension is an independent risk factor for increased VAP incidence in critically ill patients who present risk factors for IAH at admission to the ICU.

Is intra-abdominal hypertension a risk factor for ventilator-associated pneumonia?

In the last years, there has been a significant amount of research about the impact of intra-abdominal hypertension (IAH) on the outcomes of critical care patients. IAH is increasingly recognized as potential complication in intensive care unit (ICU) patients. IAH affects all body systems, most notably the cardiac, respiratory, renal, and neurologic systems. IAH affects blood flow to various organs and plays a significant role in the prognosis of the patients. Recognition of IAH, its risk factors and clinical signs can reduce the morbidity and mortality associated. Moreover, knowledge of the pathophysiology may help rationalize the therapeutic approach. On the other hand, ICU patients present frequently ventilator- associated respiratory infections. Ventilator-associated pneumonia (VAP) is the most common healthcare-associated infection (HAI) in adult critical care units. It is associated with increased ICU stay, patient ventilator days and mortality. This paper reviews the relationship between IAH and VAP. Despite animal experimentation and physiological studies on humans, in favor of the impact of IAH to VAP, there is no definitive clinical data that IAH is associated with VAP. Microaspirations form the gastrointestinal track is a pathophysiological mechanism for VAP. This review provides data suggesting that under IAH conditions bacterial translocation might be an additional responsible mechanism for VAP in those patients that merits further investigation in the future.

Intra-Abdominal Hypertension Causes Bacterial Growth in Lungs: An Animal Study.

To study the effect of intra-abdominal hypertension (IAH) on the frequency of pneumonia with an experimental study, thirteen Sprague-Dawley rats were included. Eight out of thirteen animals were randomly assigned to receive 10 ml of benzalkonium chloride 0.2% (megacolon group) and five animals received 10 ml NaCl 0.9% (controls). Animals were anaesthetized by intramuscular delivery of ketamine. The incidence of positivity for bacteria lung tissue cultures and mesenteric lymph node cultures was assessed at the 21st day after animals' sacrification, or before in case of death. All megacolon group animals presented progressive increase of the abdomen and increased IAP (≥10 mmHg) whereas the frequency of their evacuations was almost eliminated. Controls presented normal evacuations, no sign of abdominal distention, and normal IAP. In megacolon group animals, there was evidence of significant amount of bacteria in lung cultures. In contrast, no bacteria were found in control animals.

Effect of pravastatin on the frequency of ventilator-associated pneumonia and on intensive care unit mortality: open-label, randomized study.

OBJECTIVE: To investigate whether the use of pravastatin reduces the frequency of ventilator-associated pneumonia and whether it is related to favorable outcomes in critical care patients. DESIGN: Two-center, two-arm, randomized, open-label, controlled trial. SETTING: University Hospital and General Hospital of Larissa, Greece. PATIENTS: Consecutive patients were recruited from the intensive care units of the two hospitals. Patient inclusion criteria included mechanical ventilation and intensive care unit stay of >48 hrs. INTERVENTIONS: The two arms consisted of treatment plus oral pravastatin sodium (40 mg) (n = 71 patients, pravastatin group) and treatment without pravastatin (n = 81 patients, control group). Treatment was started after randomization and ended 30 days later. MEASUREMENTS AND MAIN RESULTS: Ventilator-associated pneumonia frequency and intensive care unit mortality at 30 days and at the end of intensive care unit stay were measured. Adverse events related to statin treatment in the intensive care unit were documented. Sixteen patients (22.5%) in the pravastatin group and 28 (34.5%) in the control group (p = .11) presented pneumonia during the 30-day treatment period in the intensive care unit. There was an indication for increased probability of being free from ventilator-associated pneumonia during the 30-day treatment period in the pravastatin group compared to the control group (p = .06) and significantly increased probability during the whole intensive care unit period of stay (p = .04) in the pravastatin group compared to the control group in the subgroup of patients with Acute Physiology and Chronic Health Evaluation scores of ≥ 15. Six patients (8.45%) in the pravastatin group and 16 (19.85%) in the control group died during the 30-day treatment period (p = .06), whereas 10 (14.1%) patients in the pravastatin group and 24 (29.1%) patients in the control group died during the whole period of intensive care unit stay (p = .03). Pravastatin group patients with Acute Physiology and Chronic Health Evaluation scores of ≥ 15 had significantly increased probability of survival compared to controls during the 30-day treatment period (p = .04). Creatine kinase and hepatic function enzyme levels during the whole study period were not significantly different between the pravastatin group and control group. CONCLUSION: This study provides evidence that pravastatin may favorably affect the outcome of critical care patients.