European Journal of Cardiovascular Medicine

According to a study, ventilator associated pneumonia(VAP) is a type of hospital – acquired or nosocomial pneumonia( HAP) that usually develops after endotracheal intubation (EI) more than 48-72 hours.[1] Even though according to past research authors have found, reduction in number of cases & mortality(MT) from VAP, it is still a major cause of HAP infections & MT in the intensive care unit(ICU).[2] Past research have observed a significant incidence(I) in trauma patients, upto 17.8%.[3] According to a study, this phenomenon can be attributed, to changes in immune function following major traumatic injury, as well as aspiration due to brain injury & lung contusion.[4] Study have also shown that, patients with chronic obstructive pulmonary disease (COPD) are more likely to suffer because they use invasive mechanical ventilation(MV) for longer periods of time. This weakes their muscles, cause a high rate of microaspiration & allow bacteria to colonize due to imparied mucociliary clearance and changed local & systemic defense mechanisms.[5] A study have also shown that, ARDS increases the risk of VAP.[6] Despite the implementation of lung protective strategies, incidence rate according to study was high upto 29% with ARDS patients and 35% with patients receiving extra-corporeal membrane oxygenation (ECMO).[6] According to a study, patients with a low score of Glasgow Coma Scale (GCS), are also more likely to get VAP. This is probably because comatose patients are more likely to aspirate.[7] On the hand, tracheostomy that is done early may lower the risk of VAP, but taking proton pump inhibitors (PPIs) may raise the risk of getting this condition.[7] Numerous factors affect the microorganisms associated with VAP. Some of these factors are the length of time someone is on MV& ICU before VAP started.[8] According to studies, some gram-negative bacteria that are often connected with VAP are Pseudomonas aeruginosa,

Escherichia coli, Klebsiella pneumoniae, and Acinetobacter species.[9,10] Researchers have also determined that the most prevalent Gram-positive bacterium in this particular setting is Staphylococcus aureus. [8,9,10,11]

Hence the goal of our study was to assess I, risk factor(R/F)& microbiological profile(MB-P) of VAP.

The current study was conducted in the Department of Medicine, JLN Medical College in Ajmers starting from November 2022 to ending May 2024 with 144 patients in number after the ethical approval and informed consent.

Study Design: Hospital based observational study

Inclusion Criteria:

1. >18 years with VAP
2. MV for 48 hours
3. Both sex

Exclusion Criteria:

1. Died within 96 hour
2. Develop pneumonia within 48 hrs
3. ARDS patient

Methodology

Patients were randomly selected who develop pneumonia after 48 hours and asked to fill questionnaire form ( age, sex, date of admission to ICU, inital date of MV & its indication, general & physical examination, oxygen saturation).VAS was diagnosed by modified CPIS system (0-2 point each for fever, leukocyte count, oxygenation status, quantity and purulence of tracheal secretions, type of radiographic abnormality, result of sputum culture and Gram stain. VAP group classified into 2 i.e. early onset (48-96 hr) & late onset (>96hr). Within 24 hr of admission, APACHE II scoring system was recorded for severity of disease. Our study was assesed by ch-square test & student t test.

TABLE 1: I of VAP

Table 1 shows that, maximum number of cases in here is 94(62.67%) absent, followed by present with 37.2% of them. 67.86% of cases were present as late VAP; the rest were present as early.

TABLE 2: SEX DISTRIBUTION (I)

Table 2 shows that, the maximum number of cases in VAP absent were studied (62) 65.96% in the male, followed by (32) 34.09% in the female. A similar pattern was observed in other VAP present; the maximum number of cases was observed (37) 66.07% in males, followed by (19) 33.93% in females. No statistical association was observed as the P value was 0.870.

TABLE 3: DIAGNOSIS

Table 3 shows that, OPC -PN (24.67%) followed by COPD (14%) ,CVA (10.67%) GTC-S (10.67%), CP-PN (8.00%), GBS (4.00%) No significant association was observed with VAP except GBS where cases were significantly more in VAP present as compared to VAP absent cases as the P value was 0.007.

TABLE 4: P/H of AB

Table 4 shows that, non-VAP group, 6 out of 94 patients (6.38%) had a history of antibiotic use, while in the VAP group, 20 out of 56 patients (35.71%) had used antibiotics. Overall, 26 out of 150 patients (17.33%) reported antibiotic use in the last 3 months. Thus, indicating a statistically significant difference, as the p value was <0.001, meaning that a history of iv antibiotic use is much more common in patients who developed VAP.

TABLE 5: CO-MORBIDITY (R/F)

Table 5 shows that, none of the past medical conditions (COPD, CKD, DM, or HTN) exhibit statistically significant differences between patients with or without VAP, though DM was approaching significance.

TABLE 6: RI DISTRIBUTION

Table 6 shows that, RI cases were significantly higher in VAP present cases as compared to VAP absent cases as the P value was 0.001.

TABLE 7: GCS Score

Table 7 shows that, GCS score was higher in VAP absent cases as compared to VAP present (7.99±1.343 vs. 7.29±1.486), as the p values was 0.003.

TABLE 8: COMPARISON

Table 8 shows that, mean length of ICU stay, number of ventilator days, and duration of intubation were significantly higher in VAP present cases as compared to VAP absent cases as the P value was <0.001.

TABLE 9: POSITION DISTRIBUTION

Table 9 shows that, supine position was significantly higher in VAP Present cases as compared to VAP Absent cases and vice versa as the P value was <0.001. Supine was more common in VAP present cases as compared to VAP absent cases, and vice versa were observed in propped up and semi recumbent positions as the P value was <0.001.

TABLE 10: R/F WITH DEVELOPMENT

Table 10 shows that, according to Position, Patients who were placed in a supine position were significantly more likely to develop VAP (92.86% in the VAP present group). Conversely, the propped-up and semi-recumbent positions were protective, as most patients in these positions were VAP-free. According to Poor GCS: Significantly higher in patients with VAP (16.07% vs. 4.26%). According to Use of PPI: Significantly associated with VAP (53.57% in the VAP group vs. 21.28% in the VAP-free group). According to Comorbidities COPD was more common in patients without VAP, while DM was more evenly distributed but still statistically significant.

TABLE 11: MB-P associated VAP

Table 11 shows that, significantly nonsterile cases were observed more in VAP present cases as compared to absent case (100% vs. 59.57%) as the P value was <0.001.

TABLE 12: MC-OG

Table 12 shows that, KL & PS are significantly more common in patients with VAP, while other organisms like CONS, E. coli, ST. A, and others do not show statistically significant differences between the two groups.

TABLE 13: ANTIBIOTIC (AB) SENSITIVITY (SN)

Table 13 shows that, PS is most sensitive with GTC (25.71%). KL is also commonly sensitive with GTC (20%). CONS has high resistance or sensitive with Vancomycin (60%), TCP (90%), and GTC (60%). E. coli is found with TCP and Ceftazidime. ST.A is treated mostly with TCP (66.67%) and GTC (66.67%) and COPS is only sensitive with Vancomycin and TCP.

In our study, VAP cases were 37.2% of the 150 reported cases. Among the total cases, 67.86% were identified as late-onset VAP (occurring after 96 hours), while 32.14% were classified as early-onset VAP (occurring within 96 hours). In addition to our study results, Tejerina et al. (2006) consistently reported 67.86% of late-onset VAP cases. An investigation by Tejerina et al. (2006) found that VAP affected were 15 % (439) patients nout of the total patient group.[12] According to Gadani H et al. (2010), the incidence of early-onset VAP was reported to be 27.02%.[13] Resende et al. (2013) did a study that found 26.2% of patients who had invasive MV for at least 48 hours & also showed VAP.[14] The variability in VAP rates observed across studies may be influenced by several factors, including the population under investigation, the environmental context, and the criteria used to distinguish between early & late-onset VAP.[15] The prevalence of VAP among Serbian patients with severe head injuries was recorded at 49.7%, significantly exceeding the global average. [16] Ahmed Abdelrazik (2017) reported that VAP occured in 35.4% (17 out of total patients). [17] Ding et al. (2017) said that the total cumulative incidence of VAP in mainland China was 23.8%, with a 95% confidence interval of 20.6% to 27.2%. The results of this investigation revealed a notable level of heterogeneity, indicating variability across different contexts in China. [18] Another study reported a prevalence rate of 35% for VAP.[19] Our investigation looked into the relationship between sex and VAP and found no statistically significant difference by examining the maximum number of cases of VAP absent, which was 62, with 65.96% occurring in males and 34.09% in females, represented by 32 cases. A comparable trend was noted in other cases of VAP, with the highest incidence recorded at 37, representing 66.07% in males, and 19 cases, accounting for 33.93% in females. A comparable trend was noted in other cases of VAP; the highest incidence was recorded at 37, representing 66.07% in males, while females accounted for 19 cases, or 33.93%. There were more men in both groups, with more men in cases where VAP was present and cases where it wasn't. However, the statistical analysis showed that there was no significant link between sex and VAP status (P value = 0.873, not significant). The findings indicate that sex did not serve as a significant determinant for the incidence of VAP in this study.[20] The present investigation examined the relationship between primary underlying diagnoses and the occurrence of VAP. We identified OPC-PN as the primary underlying diagnosis in the majority of cases (24.67%), followed by COPD (14%).Cerebrovascular accident (10.67%) GTC-S occurred in 10.67% of cases, CP-PN (8.00%) & GBS (4.00%). A strong link was found between VAP and none of the other conditions. The only exception was GBS, which was much more common in people with VAP than in people without it as the P value was 0.007. Researchers reported that the main cause of VAP is the breathing in of oropharyngeal pathogens & the leakage of secretions containing bacteria around the endotracheal tube.[19] We found a significant association between a history of AB usage(UG), hospitalization in the last 3 months, and VAP. The AB-UG history was lower in the VAP group (20 out of 56 patients, or 35.71%) than in the non-VAP group (6 out of 94 patients, or 6.38 percent). A study observed independent risk factors for medication resistance in VAP pathogens, prior AB therapy and hospitalization for more than 5 days. [19] Long-term antibiotic exposure was found to be a powerful predictor of antibiotic resistance by Lewis et al. (2018).[21] They also found two separate risk factors for multidrug-resistant VAP, being exposed to AB before they become resistant and using AB over and over again that are not effective enough. These results underscore how recent AB-UG has contributed to the spread of VAP, notably via mechanisms of AB resistance.[21]

Gadani H. et al., study from 2010 showed that VAP is much more common in patients who are stuporous (62.5%) and comatose (50%) than in patients who are conscious (35.75%) and drowsy (18.42%) showed p-value of 0.0023 which means difference was statistically significant.[13] Thus author may attribute this phenomenon to the increased risk of aspiration in comatose patients. Therefore, these results show that lower GCS scores are linked to a higher risk of VAP. This means that lower GCS scores could be a key indicator of when VAP will happen.[13] Ding C et al. (2017) revealed that older age (≥60 years), coma, re-intubation, tracheotomy, and extended breathing were substantially linked with the incidence of VAP. [18] Similar study observations were taken during the other studies too Liu Y et al 2017 found that the independent risk factors for VAP were advanced age, current smoking status, chronic obstructive pulmonary disease, and a higher simplified acute physiology score system II upon admission. The median length of stay in the ICU for patients who did or did not develop VAP was 8.0 and 6.5 days, respectively (P = 0.006). A study identified reintubation as a significant risk factor for the development of VAP. The study reported an odds ratio suggesting that patients who underwent reintubation had an almost threefold increased likelihood of developing VAP in comparison to those who did not require reintubation. [22] Another study determined that effective management of respiratory failure, aimed at minimizing the necessity for reintubation, could substantially decrease the rates of VAP.[23] We also found that, the supine position due to some medical condition was significantly higher in VAP Present cases as compared to VAP Absent cases and vice versa in the supine position (P<0.001S). Supine was more common in VAP present cases as compared to VAP absent cases, and vice versa were observed in propped up and semi recumbent positions (P<0.001S). We also found significantly more nonsterile cases were observed in VAP-present cases than in VAP-absent cases (100% vs. 59.57%), with a P value of less than 0.001. This suggests that there is a considerable correlation between the existence of VAP and the isolation of pathogens. When it comes to addressing VAP, a bacteriological approach is essential. This is because it helps distinguish between infecting pathogens and colonizers, which means that over-treatment of the former is prevented.[24] Rhodes et al. (2018) and Evans et al. (2018) verified the prevalence of the common pathogens associated with VAP.[25,26] Researchers Evans C. R. et al. (2018) found that both Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) were more common than they used to be, with 23% and 10% more cases, compared to 17% and 6%, respectively. This finding emphasizes the growing prevalence of resistant strains.[26]

Jovanovic et al. (2015) reported that Acinetobacter spp. was the most common pathogen in patients with both early and late-onset VAP.[15] Husain Shabbir Ali (2016) Identified Gram-negative bacilli, with Pseudomonas spp. being the most common, as frequent respiratory specimen isolates.[27] These findings underline the predominance of KL & PS in VAP cases and highlight the significant role of PS in the development of VAP. The consistency with findings from other studies emphasizes the need for targeted AMB strategies to address these common pathogens. The current study shows the Association of SN to AB according to VAP. The analysis of AB-SN in relation to VAP revealed key insights into the usage patterns of various AB. The most commonly consumed AB was Aztreonam (25.53%), followed by Ciprofloxacin (22.34%) and Piperacillin-Tazobactam (18.09%). Another study noted that AB-SN patterns in VAP varied based on regional differences, hospital infection control practices, and empirical treatment approaches. Similar to our study, they found that there was no significant.[28] The findings underscore the increasing problem of multidrug resistance in VAP pathogens. Effective management of VAP requires careful selection of antibiotics, considering the high resistance rates of common pathogens such as Acinetobacter and ST.A. Colistin emerges as a crucial treatment for MDR strains, while polymyxin B, tigecycline, and vancomycin should be reserved for severe, resistant infections. These insights emphasize the need for on going surveillance of resistance patterns and prudent antibiotic use to manage VAP effectively.[28]

The study highlights prolonged mechanical breathing, aspiration, and even some primary illnesses like GBS as important risk factors. Comorbidities such as COPD and DM, as well as prior antibiotic usage and recent hospitalization, were all significantly associated with VAP. In addition to the above, the most common pathogens in VAP cases were Pseudomonas and Klebsiella, and antibiotic resistance poses a significant issue. To avoid multidrug-resistant (MDR) pathogens, proper antibiotic stewardship is crucial.

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