Hospital Pneumonia

Prema smjernicama Američkoga torakalnog društva (ATS) i Američkog društva za zarazne bolesti (IDSA) iz 2005. godine, razlikujemo tri tipa bolničkih pneumonija: bolnička pneumonija u užem smislu (HAP), pneumonija povezana s respiratorom (VAP) i pneumonija povezana sa zdravstvenom skrbi (HCAP). HAP nosi najveću smrtnost među bolničkim infekcijama. Rizik od nastanka pneumonije povećava se boravkom u jedinicama intenzivnog liječenja. Infekcija nastaje mikroaspiracijom bakterija iz koloniziranog orofaringealnog trakta i može biti polimikrobna te multirezistentna na lijekove (MDR). MDR je rezistencija bakterije na dva ili više antibiotika koji se uobičajeno rabe u njezinu liječenju. Infekcija MDR-mikroorganizmima očekuje se u bolesnika s određenim čimbenicima rizika: nedavna upotreba antibiotika, nedavni ili produljeni boravak u bolnici, komorbiditet, kritično stanje bolesnika te izloženost lokalnoj mikrobiološkoj flori. Osim kliničkih parametara (naglo nastala vrućica, purulentna traheobronhalna sekrecija, respiratorno urušavanje) za dijagnozu HAP-a, VAP-a i HCAP-a potrebno je pouzdano mikrobiološko uzorkovanje s analizom kulture uz radiološki nalaz novog ili progredirajućeg infiltrata na plućima. S obzirom na visok mortalitet, liječenje suspektnog HAP-a, VAP-a i HCAP-a ne smije se odgađati te empirijski treba primijeniti antibiotik širokog spektra. Ako su odsutni čimbenici rizika od MDR-infekcije, empirijski se koristimo monoterapijom (beta-laktamima ili fluorokinolonima). Pri sumnji na infekciju MDR-uzročnikom izbor je empirijskog liječenja kombinacija lijekova. „Prekrajanjem“ početno širokog antibiotskog liječenja prema nalazu testa osjetljivosti (deeskalacija) te kraćom primjenom antibiotika smanjuje se rizik od nove multirezistencije, toksičnosti kombiniranog liječenja i bolničke smrtnosti.Three types of hospital pneumonia are recognised by the 2005 American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) guidelines: Hospital-acquired pneumonia (HAP), Ventilator-associated pneumonia (VAP) and healthcare-associated pneumonia (HCAP). Among all the hospital-acquired infections HAP is responsible for highest mortality rate. The stay in intensive care units increases the risk of pneumonia. Infection develops through microaspiration of bacteria from colonized oropharyngeal tract and may be polymicrobial and caused by multidrug resistant (MDR) pathogens. MDR is defined as resistance of bacteria to two or more antibiotics ordinarily used to treat this microorganism. MDR infection is expected in patients with certain risk factors: recent antibiotic use, recent or prolonged hospital stay, comorbidity, critical illness and exposure to local microbial flora. Besides clinical features (sudden onset fever, purulent tracheobronchial secretions, respiratory deterioration), the diagnosis of HAP, VAP and HCAP is made upon reliable microbiologic sampling and culture analysis in relation to the chest radiograph findings of new or progressive infiltrate. Considering a high mortality rate, the treatment of suspected HAP, VAP and HCAP should not be delayed and empiric broad spectrum antibiotic should be instituted. Empiric antibiotic monotherapy (beta-lactams or fluoroquinolones) is used in the absence of known risk factors for MDR infection. When MDR infection is suspected, empiric combination of drugs is the choice. Tailoring the broad spectrum therapy after susceptibility tests (de-escalation) and shortening the therapy duration reduces the risk of additional drug-resistance, toxicity of combination therapy and in-hospital mortality

Harmonic Structure of Tracheal Biometrics

According to existing research, in 20% of patients the required tracheal size (diameter and length) could not be measured automatically (using software solution). In this paper, we use Zederbauer\u27s harmonic circle to define the relationship between a person\u27s body height and the diameter and length of their trachea. We then explore differences by gender. The results show that there is a highly significant correlation between measured data and values obtained by harmonic analysis. The final goal is to obtain the mathematical interpretation of the relationship of the tracheal size to the height of man, in order to further apply such sizes in the creation of 3D models that could finally be printed on appropriate 3D printers and with the suitable material

Hospital Pneumonia

Prema smjernicama Američkoga torakalnog društva (ATS) i Američkog društva za zarazne bolesti (IDSA) iz 2005. godine, razlikujemo tri tipa bolničkih pneumonija: bolnička pneumonija u užem smislu (HAP), pneumonija povezana s respiratorom (VAP) i pneumonija povezana sa zdravstvenom skrbi (HCAP). HAP nosi najveću smrtnost među bolničkim infekcijama. Rizik od nastanka pneumonije povećava se boravkom u jedinicama intenzivnog liječenja. Infekcija nastaje mikroaspiracijom bakterija iz koloniziranog orofaringealnog trakta i može biti polimikrobna te multirezistentna na lijekove (MDR). MDR je rezistencija bakterije na dva ili više antibiotika koji se uobičajeno rabe u njezinu liječenju. Infekcija MDR-mikroorganizmima očekuje se u bolesnika s određenim čimbenicima rizika: nedavna upotreba antibiotika, nedavni ili produljeni boravak u bolnici, komorbiditet, kritično stanje bolesnika te izloženost lokalnoj mikrobiološkoj flori. Osim kliničkih parametara (naglo nastala vrućica, purulentna traheobronhalna sekrecija, respiratorno urušavanje) za dijagnozu HAP-a, VAP-a i HCAP-a potrebno je pouzdano mikrobiološko uzorkovanje s analizom kulture uz radiološki nalaz novog ili progredirajućeg infiltrata na plućima. S obzirom na visok mortalitet, liječenje suspektnog HAP-a, VAP-a i HCAP-a ne smije se odgađati te empirijski treba primijeniti antibiotik širokog spektra. Ako su odsutni čimbenici rizika od MDR-infekcije, empirijski se koristimo monoterapijom (beta-laktamima ili fluorokinolonima). Pri sumnji na infekciju MDR-uzročnikom izbor je empirijskog liječenja kombinacija lijekova. „Prekrajanjem“ početno širokog antibiotskog liječenja prema nalazu testa osjetljivosti (deeskalacija) te kraćom primjenom antibiotika smanjuje se rizik od nove multirezistencije, toksičnosti kombiniranog liječenja i bolničke smrtnosti.Three types of hospital pneumonia are recognised by the 2005 American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) guidelines: Hospital-acquired pneumonia (HAP), Ventilator-associated pneumonia (VAP) and healthcare-associated pneumonia (HCAP). Among all the hospital-acquired infections HAP is responsible for highest mortality rate. The stay in intensive care units increases the risk of pneumonia. Infection develops through microaspiration of bacteria from colonized oropharyngeal tract and may be polymicrobial and caused by multidrug resistant (MDR) pathogens. MDR is defined as resistance of bacteria to two or more antibiotics ordinarily used to treat this microorganism. MDR infection is expected in patients with certain risk factors: recent antibiotic use, recent or prolonged hospital stay, comorbidity, critical illness and exposure to local microbial flora. Besides clinical features (sudden onset fever, purulent tracheobronchial secretions, respiratory deterioration), the diagnosis of HAP, VAP and HCAP is made upon reliable microbiologic sampling and culture analysis in relation to the chest radiograph findings of new or progressive infiltrate. Considering a high mortality rate, the treatment of suspected HAP, VAP and HCAP should not be delayed and empiric broad spectrum antibiotic should be instituted. Empiric antibiotic monotherapy (beta-lactams or fluoroquinolones) is used in the absence of known risk factors for MDR infection. When MDR infection is suspected, empiric combination of drugs is the choice. Tailoring the broad spectrum therapy after susceptibility tests (de-escalation) and shortening the therapy duration reduces the risk of additional drug-resistance, toxicity of combination therapy and in-hospital mortality

Neinvazivna mehanička ventilacija u akutnoj respiracijskoj insuficijenciji zbog COVID-19

Coronavirus disease 2019 (COVID-19) is presented with a wide range of symptoms, from asymptomatic disease to severe and progressive interstitial pneumonia. As part of interstitial pneumonia, respiratory failure is typically presented as hypoxia and is the most common cause of hospitalization. When oxygen therapy fails, continuous positive airway pressure (CPAP) or noninvasive mechanical ventilation (NIV) are used as respiratory support measures of first choice. Noninvasive respiratory support (NIRS) is applied in order to save intensive care unit resources and to avoid complications related to invasive mechanical ventilation. Emerging evidence has shown that the use of CPAP or NIV in the management of acute hypoxemic respiratory failure in COVID-19 reduces the need for intubation and mortality. The advantage of NIRS is the feasibility of its application on wards. NIV could be administered via a face mask or helmet interface. Helmet adheres better than mask and therefore leakage is reduced, a delivery of positive end-expiratory pressure is more accurate, and the risk of nosocomial transmission of infections is lowered. Patients on NIRS must be carefully monitored so that further respiratory deterioration is not overlooked and additional measures of care including timely intubation and invasive mechanical ventilation could be performed if needed.Bolest uzrokovana novim koronavirusom 2019 (COVID-19) prezentira se širokim rasponom simptoma, od asimptomatske bolesti do teške i progresivne intersticijske upale pluća. Kao dio intersticijske pneumonije respiracijska insuficijencija tipično je obilježena hipoksijom i najčešći je uzrok hospitalizacije. Kada terapija kisikom ne uspije, kontinuirani pozitivni tlak u dišnim putovima (CPAP) ili neinvazivna mehanička ventilacija (NIV) mjere su respiracijske potpore prvog izbora. Neinvazivna respiracijska potpora (NIRS) primjenjuje se kako bi se uštedjeli resursi jedinica intenzivnog liječenja i izbjegle komplikacije povezane s invazivnom mehaničkom ventilacijom. Uporaba CPAP-a ili NIV-a u liječenju akutne hipoksemične respiracijske insuficijencije kod COVID-19 smanjuje potrebu za intubacijom i smrtnost. Prednost NIRS-a je da se može provoditi na odjelima. NIV se može primijeniti preko maske ili kacige. Kaciga bolje prianja u odnosu na masku i stoga je smanjen gubitak zraka, isporuka pozitivnog tlaka na kraju izdisaja je točnija, a rizik od nozokomijalnog prijenosa infekcija je manji. Bolesnici na NIRS-u moraju se pažljivo nadzirati kako se ne bi previdjelo daljnje respiracijsko pogoršanje i kako bi se mogle provesti dodatne mjere skrbi uključujući pravodobnu intubaciju i invazivnu mehaničku ventilaciju

Anemia, hypoalbuminemia, and elevated troponin levels as risk factors for respiratory failure in patients with severe exacerbations of chronic obstructive pulmonary disease requiring invasive mechanical ventilation

Aim To determine in-hospital and post-discharge mortality, readmission rates, and predictors of invasive mechanical ventilation (IMV) in patients treated at intensive care unit (ICU) due to acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Methods A retrospective observational cohort study included all patients treated at a respiratory ICU for AECOPD during one year. A total of 62 patients (41 men) with mean age 68.4 ± 10.4 years were analyzed for outcomes including in-hospital and post-discharge mortality, readmission rates, and IMV. Patients’ demographic, hematologic, biochemical data and arterial blood gas (ABG) values were recorded on admission to hospital. Mean duration of followup time was 2.4 years. Results Of 62 patients, 7 (11.3%) died during incident hospitalization and 21 (33.9%) died during the follow-up. The overall 2.4-year mortality was 45.2%. Twenty nine (46.8%) patients were readmitted due to AECOPD. The average number of readmissions was 1.2. Multivariate analysis showed that blood pH, bicarbonate levels, low albumin, low serum chloride, and low hemoglobin were significant predictors of IMV during incident hospitalization (P < 0.001 for the overall model fit). Conclusion High in-hospital and post-discharge mortality and high readmission rates in our patients treated due to AECOPD at ICU indicate that these patients represent a high risk group in need of close monitoring. Our results suggested that anemia, hypoalbuminemia, and elevated troponin levels were risk factors for the need of IMV in severe AECOPD. Identification of such high-risk patients could provide the opportunity for administration of an appropriate and timely treatment

Value of Rapid Aetiological Diagnosis in Optimization of Antimicrobial Treatment in Bacterial Community Acquired Pneumonia

In 80 adult patients with community acquired pneumonia (CAP) conventional microbiological methods, polymerase chain reaction (PCR) and serum C-reactive protein (CRP) levels were performed and the appropriateness of the empirical antimicrobial treatment was evaluated according to bacterial pathogen detected. The aetiology was determined in 42 (52.5%) patients, with Streptococcus pneumoniae as the most common pathogen. PCR applied to bronchoalveolar lavage (BAL) provided 2 and PCR on sputum samples 1 additional aetiological diagnosis of CAP. The mean CRP values in the S. pneumoniae group were not significantly higher than in the group with other aetiological diagnoses (166.89 mg/L vs.160.11 mg/L, p=0.457). In 23.8% (10/42) of patients with determined aetiology, the empirical antimicrobial treatment was inappropriate. PCR tests need further investigation, particularly those for the atypical pathogens, as they are predominant in inappropriately treated patients. Our results do not support the use of CRP as a rapid test to guide the antimicrobial treatment in patients with CAP

NONINVASIVE VENTILATION IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE

Neinvazivna mehanička ventilacija (NIV) je ventilacija pozitivnim tlakom primijenjena preko neinvazivnih sučelja. Smatra se standardnim načinom zbrinjavanja bolesnika hospitaliziranih zbog globalne respiracijske insufi cijencije u sklopu akutnog pogoršanja kronične opstruktivne plućne bolesti (KOPB). NIV poboljšava izmjenu plinova, smanjuje dišni rad i posljedično omogućava oporavak dišne muskulature. Dokazano je da NIV može reducirati potrebu za intubacijom, morbiditet i mortalitet pacijenata s teškim pogoršanjem KOPB-a. NIV skraćuje vrijeme liječenja u jedinicama intenzivne skrbi i ukupno trajanje bolničkog liječenja. Može se koristiti u svrhu olakšavanja odvajanja bolesnika od invazivne mehaničke ventilacije i prevenciji razvoja respiracijske insufi cijencije nakon ekstubacije. U bolesnika s teškom respiracijskom acidozom i poremećajem svijesti postoji visok rizik neuspjeha liječenja NIV-om. U tih bolesnika liječenje NIV-om treba provoditi uz intenzivni nadzor i u uvjetima koji omogućavaju brzu endotrahejsku intubaciju u slučaju potrebe. Kontroverzni su podatci o koristi dugotrajne primjene NIV-a u stabilnom KOPB-u. U odnosu na standardno liječenje, primjena NIV-a visokog intenziteta poboljšava ishode ovih bolesnika. NIV visokog intenziteta poboljšava izmjenu dišnih plinova, plućnu funkciju, kvalitetu života vezanu uz zdravlje, podnošenje fi zičkog napora i preživljenje. Dodatak NIV-a u stabilnoj fazi bolesti programu respiratorne rehabilitacije poboljšava rezultate respiratorne rehabilitacije. S obzirom da NIV pruža niz koristi bolesnicima s KOPB-om svaki bi liječnik koji je uključen u liječenje ovih bolesnika trebao vladati ovom tehnikom.Noninvasive ventilation (NIV) refers to positive pressure ventilation that is delivered through a noninvasive interface. It is considered as a standard treatment for patients admitted to hospital with hypercapnic respiratory failure secondary to acute exacerbation of chronic obstructive pulmonary disease (COPD). NIV improves gas exchange and reduces respiratory muscle work, consequently allowing respiratory muscle recovery. The available evidence establishes that NIV might reduce intubation, morbidity and mortality rates in patients with severe COPD exacerbations. NIV shortens intensive care unit and total hospital lengths of stay. It can be used to facilitate the process of weaning from mechanical ventilation and prevent development of post-extubation respiratory failure. Patients with severe respiratory acidosis or with altered levels of consciousness due to carbon dioxide retention are at a high risk of NIV failure. In these patients, a NIV trial should be attempted in closely monitored clinical conditions where prompt endotracheal intubation may be performed. The benefi ts of long-term NIV management of stable COPD are still controversial. However, implementation of high-intensity NIV has been shown to improve outcomes in this patient group. High-intensity NIV improves gas exchange, lung function, health-related quality of life, exercise tolerance and survival compared to standard care alone. In stable severe COPD, the addition of NIV to a pulmonary rehabilitation program improves outcomes as compared to pulmonary rehabilitation alone. Since NIV provides signifi cant benefi ts in COPD, every physician who is involved in the treatment of these patients should be familiar with this technique

Influence of the initial continuous positive airway pressure treatment on REM sleep in patients with sleep apnea syndromes

Na temelju dosadašnjih istraživanja postavili smo hipotezu da prvotna primjena kontinuiranoga pozitivnoga tlaka zraka u dišnim putevima (CPAP) dovodi do normalizacije respiracijskih parametara i oporavka REM-a u bolesnika s apnejom u spavanju. Centralna apneja u spavanju (CSA) do sada nije istraživana u tome smislu. Pretpostavili smo veći učinak CPAP-a na REM u bolesnika s opstruktivnom apnejom u spavanju (OSA), osobito u podskupini OSA-e s predominacijom mješovitih epizoda, a manji u bolesnika s CSA-om. Retrospektivno smo analizirali demografske i komorbiditetne podatke te usporedili polisomnografske izvještaje prije i nakon CPAP-a u odraslih bolesnika s umjerenom i teškom apnejom u spavanju evaluiranih u našem laboratoriju. U studiju je uključeno dvjestošezdeset bolesnika (183 s predominacijom opstruktivnih epizoda apneje, 61 s predominacijom mješovitih epizoda, 16 s predominacijom centralnih epizoda). Hipertenzija je bila jedina značajna razlika u karakteristikama među trima skupinama. Statistički značajan oporavak REM-a nakon CPAP-a ustanovljen je u svih bolesnika s apnejom u spavanju, osobito u opstruktivnoj i mješovitoj skupini (bez značajne međusobne razlike), no nedovoljan u centralnoj – usprkos uspješnoj korekciji apneja-hipopneja indeksa (AHI) u sve tri skupine. Predloženi su drugi čimbenici odgovorni za nedovoljan oporavak REM-a u CSA-e nakon CPAP-a. Zaključujemo da je povećanje REM-a u apneje u spavanju nakon prvotne primjene CPAP-a snažno povezano s korekcijom AHI-ja.Regarding former studies, we hypothesized that initial continuous positive airway pressure (CPAP) treatment is leading to the respiratory normalization and rapid eye movement (REM) rebound in patients with sleep apnea. Central sleep apnea (CSA) was not evaluated in this regard so far. We anticipated better effect of CPAP on REM in obstructive sleep apnea (OSA) patients, especially in OSA with mixed apnea-predominant subgroup, and lesser in CSA patients. We retrospectively analyzed data regarding demographics and comorbidities and compared polysomnography reports before and after initial CPAP of moderate and severe sleep apnea patients evaluated in our sleep lab. Two hundred and sixty patients (183 obstructive apnea-predominant, 61 mixed apnea-predominant, 16 central apnea-predominant) were included in the study. Hypertension was the only significantly different characteristic among three groups. Statistically significant REM rebound after CPAP was found in all sleep apnea patients, especially in obstructive and mixed apnea groups (without the difference between the groups), but insignificant in central apnea group – regardless of successful apneahypopnea index (AHI) reduction in all three groups. Other factors responsible for lack of REM rebound in CSA after CPAP were proposed. We conclude that REM rebound in sleep apnea following first CPAP usage strongly correlated with AHI reduction

Influence of the initial continuous positive airway pressure treatment on REM sleep in patients with sleep apnea syndromes

Na temelju dosadašnjih istraživanja postavili smo hipotezu da prvotna primjena kontinuiranoga pozitivnoga tlaka zraka u dišnim putevima (CPAP) dovodi do normalizacije respiracijskih parametara i oporavka REM-a u bolesnika s apnejom u spavanju. Centralna apneja u spavanju (CSA) do sada nije istraživana u tome smislu. Pretpostavili smo veći učinak CPAP-a na REM u bolesnika s opstruktivnom apnejom u spavanju (OSA), osobito u podskupini OSA-e s predominacijom mješovitih epizoda, a manji u bolesnika s CSA-om. Retrospektivno smo analizirali demografske i komorbiditetne podatke te usporedili polisomnografske izvještaje prije i nakon CPAP-a u odraslih bolesnika s umjerenom i teškom apnejom u spavanju evaluiranih u našem laboratoriju. U studiju je uključeno dvjestošezdeset bolesnika (183 s predominacijom opstruktivnih epizoda apneje, 61 s predominacijom mješovitih epizoda, 16 s predominacijom centralnih epizoda). Hipertenzija je bila jedina značajna razlika u karakteristikama među trima skupinama. Statistički značajan oporavak REM-a nakon CPAP-a ustanovljen je u svih bolesnika s apnejom u spavanju, osobito u opstruktivnoj i mješovitoj skupini (bez značajne međusobne razlike), no nedovoljan u centralnoj – usprkos uspješnoj korekciji apneja-hipopneja indeksa (AHI) u sve tri skupine. Predloženi su drugi čimbenici odgovorni za nedovoljan oporavak REM-a u CSA-e nakon CPAP-a. Zaključujemo da je povećanje REM-a u apneje u spavanju nakon prvotne primjene CPAP-a snažno povezano s korekcijom AHI-ja.Regarding former studies, we hypothesized that initial continuous positive airway pressure (CPAP) treatment is leading to the respiratory normalization and rapid eye movement (REM) rebound in patients with sleep apnea. Central sleep apnea (CSA) was not evaluated in this regard so far. We anticipated better effect of CPAP on REM in obstructive sleep apnea (OSA) patients, especially in OSA with mixed apnea-predominant subgroup, and lesser in CSA patients. We retrospectively analyzed data regarding demographics and comorbidities and compared polysomnography reports before and after initial CPAP of moderate and severe sleep apnea patients evaluated in our sleep lab. Two hundred and sixty patients (183 obstructive apnea-predominant, 61 mixed apnea-predominant, 16 central apnea-predominant) were included in the study. Hypertension was the only significantly different characteristic among three groups. Statistically significant REM rebound after CPAP was found in all sleep apnea patients, especially in obstructive and mixed apnea groups (without the difference between the groups), but insignificant in central apnea group – regardless of successful apneahypopnea index (AHI) reduction in all three groups. Other factors responsible for lack of REM rebound in CSA after CPAP were proposed. We conclude that REM rebound in sleep apnea following first CPAP usage strongly correlated with AHI reduction

Influence of the initial continuous positive airway pressure treatment on REM sleep in patients with sleep apnea syndromes

Na temelju dosadašnjih istraživanja postavili smo hipotezu da prvotna primjena kontinuiranoga pozitivnoga tlaka zraka u dišnim putevima (CPAP) dovodi do normalizacije respiracijskih parametara i oporavka REM-a u bolesnika s apnejom u spavanju. Centralna apneja u spavanju (CSA) do sada nije istraživana u tome smislu. Pretpostavili smo veći učinak CPAP-a na REM u bolesnika s opstruktivnom apnejom u spavanju (OSA), osobito u podskupini OSA-e s predominacijom mješovitih epizoda, a manji u bolesnika s CSA-om. Retrospektivno smo analizirali demografske i komorbiditetne podatke te usporedili polisomnografske izvještaje prije i nakon CPAP-a u odraslih bolesnika s umjerenom i teškom apnejom u spavanju evaluiranih u našem laboratoriju. U studiju je uključeno dvjestošezdeset bolesnika (183 s predominacijom opstruktivnih epizoda apneje, 61 s predominacijom mješovitih epizoda, 16 s predominacijom centralnih epizoda). Hipertenzija je bila jedina značajna razlika u karakteristikama među trima skupinama. Statistički značajan oporavak REM-a nakon CPAP-a ustanovljen je u svih bolesnika s apnejom u spavanju, osobito u opstruktivnoj i mješovitoj skupini (bez značajne međusobne razlike), no nedovoljan u centralnoj – usprkos uspješnoj korekciji apneja-hipopneja indeksa (AHI) u sve tri skupine. Predloženi su drugi čimbenici odgovorni za nedovoljan oporavak REM-a u CSA-e nakon CPAP-a. Zaključujemo da je povećanje REM-a u apneje u spavanju nakon prvotne primjene CPAP-a snažno povezano s korekcijom AHI-ja.Regarding former studies, we hypothesized that initial continuous positive airway pressure (CPAP) treatment is leading to the respiratory normalization and rapid eye movement (REM) rebound in patients with sleep apnea. Central sleep apnea (CSA) was not evaluated in this regard so far. We anticipated better effect of CPAP on REM in obstructive sleep apnea (OSA) patients, especially in OSA with mixed apnea-predominant subgroup, and lesser in CSA patients. We retrospectively analyzed data regarding demographics and comorbidities and compared polysomnography reports before and after initial CPAP of moderate and severe sleep apnea patients evaluated in our sleep lab. Two hundred and sixty patients (183 obstructive apnea-predominant, 61 mixed apnea-predominant, 16 central apnea-predominant) were included in the study. Hypertension was the only significantly different characteristic among three groups. Statistically significant REM rebound after CPAP was found in all sleep apnea patients, especially in obstructive and mixed apnea groups (without the difference between the groups), but insignificant in central apnea group – regardless of successful apneahypopnea index (AHI) reduction in all three groups. Other factors responsible for lack of REM rebound in CSA after CPAP were proposed. We conclude that REM rebound in sleep apnea following first CPAP usage strongly correlated with AHI reduction