Intra-abdominal hypertension and increased acute kidney injury risk: a systematic review and meta-analysis.

OBJECTIVE: The present meta-analysis aimed to determine the relationship between intra-abdominal hypertension (IAH) and an increased prevalence of acute kidney injury (AKI) and identify the associated risk factors in various patient populations, regardless of whether they were admitted to an intensive care unit. METHODS: We used three databases for the following search terms: "IAH," "abdominal compartment syndrome," "AKI," "acute kidney failure," and others. The articles retrieved were compared to identify appropriate studies published until 7 May 2020. The main outcome was AKI. RESULTS: Six studies with 344 individuals were included. The patients were divided into two main groups: the IAH and non-IAH groups. Compared with patients without IAH, patients with IAH had a higher risk of AKI (odds ratio = 2.57, 95% confidence interval: 1.55-4.26). In the subgroup and meta-regression analyses, body mass index, age, the presence or absence of burns, and cardiac surgery did not affect the risk of AKI. CONCLUSION: IAH was associated with AKI risk, and this association was not influenced by age, body mass index, the presence or absence of burns, or cardiac surgery.

Hipertensão intra-abdominal e síndrome compartimental abdominal: repercussões e tratamento clínico no paciente crítico / Intra-abdominal hypertension and abdominal compartment syndrome: repercussions and clinical treatment in critically ill patients

A hipertensão intra-abdominal e a síndrome compartimental abdominal foram durante muitas décadas mal compreendidas e dissociadas de suas repercussões clínicas. Trata-se de um distúrbio que pode levar à disfunção de múltiplos órgãos devido ao desequilíbrio circulatório desencadeado pelo aumento de pressão no compartimento abdominal. As manifestações envolvem os sistemas cardiovascular, respiratório, renal, nervoso e gastrintestinal e estão largamente relacionadas com o fator de morbimortalidade no paciente crítico. A despeito da importância clínica, a hipertensão intra-abdominal e à síndrome compartimental abdominal ainda são temas pouco dominados pelos médicos, e fazem-se necessários o reconhecimento precoce e o estabelecimento de estratégias clínicas objetivas no contexto de uma síndrome com desfecho tão desfavorável. Portanto, foi realizada uma revisão da literatura não sistematizada com objetivo de compreender os principais pontos sobre definições, prevalência, fatores de risco, fisiopatologia, diagnóstico e tratamento acerca da hipertensão intra-abdominal e a síndrome compartimental abdominal.

Intra-abdominal hypertension and abdominal compartment syndrome have been, for many decades, poorly understood and dissociated from their clinical repercussions. It is a disorder that can lead to organ dysfunction due to circulatory impairment triggered by increased pressure in the abdominal compartment. The manifestations involve cardiovascular, respiratory, renal, nervous, and gastrointestinal systems, and are widely associated with significant morbidity and mortality in critically ill patients. Despite their clinical importance, intra-abdominal hypertension and abdominal compartment syndrome are still not sufficiently known by physicians and, early recognition and the establishment of objective clinical strategies for managing these highly morbid syndromes are required. Therefore, a non-systematized review was carried out to understand the main points about definitions, prevalence, risk factors, pathophysiology, diagnosis, and treatment of intra-abdominal hypertension and abdominal compartment syndrome.

Intra-abdominal Hypertension as a Cause of Oliguric Acute Kidney Injury in a Patient with Chronic Lymphocytic Leukemia.

Acute kidney injury (AKI) is a well-known complication in patients with chronic lymphocytic leukemia (CLL). It could occur via diverse mechanisms such as leukemic infiltration, extrarenal obstruction, tumor lysis syndrome, glomerular diseases, and medication side effects. The incidence of kidney disease at the diagnosis of CLL is about 10%. We report a case of AKI, in a patient with a known history of CLL, due to abdominal compartment syndrome, caused by extremely enlarged intra-abdominal lymph masses. To the best of our knowledge, no case of AKI due to such cause has been reported so far.

Prevalence of intra-abdominal hypertension in horses with colic.

OBJECTIVE: To determine an abdominal pressure cutoff value for intra-abdominal hypertension (IAH) in the horse and characterize IAH in horses with acute colic. DESIGN: Prospective clinical cohort. SETTING: University teaching hospital. ANIMALS: Nine healthy adult horses and 56 horses with acute colic. INTERVENTIONS: Ventral intra-abdominal pressure (IAP) was measured in triplicate at end expiration and averaged. Each colic case was classified as medical or surgical and large intestine (LI) or small intestine (SI). Management and final outcome (alive, euthanized, or died) were recorded. IAH was defined as ≥32 mm Hg (mean + 2 SDs of ventral IAP in control horses). Proportions of horses with and without IAH for different lesions were expressed as fractions and percentages. Differences in IAP between groups were determined using ANOVA with post-testing or t-tests. Odds ratio for management strategy (ie, need for medical or surgical) in horses with IAH was performed using Fisher's exact test. P < 0.05 was considered significant. MEASUREMENTS AND MAIN RESULTS: IAP was higher in horses with colic compared to controls (P = 0.025). Over 18 months, 30.4% of horses with colic had IAH (n = 10 LI lesions, n = 7 SI lesions). Horses with LI medical lesions had the highest IAP of all lesions (mean 36.5 mm Hg). IAH horses with medical lesions were 15 times more likely to survive than IAH horses requiring surgery (P = 0.03). CONCLUSIONS: Acute colic in horses is associated with an increased ventral IAP compared with healthy controls. IAH does exist in horses with colic, notably LI medical lesions, and is associated with nonsurvival in horses that require surgery.

Intracranial Hypertension and Intra-abdominal Pressure. Is it Worth Measuring?

Patients with refractory intracranial hypertension who have already undergone all the measures recommended by the current guidelines can benefit from having their intraabdominal pressure monitored since its increase generates hemodynamic repercussions and secondary elevation of intracranial pressure. In this context, a bibliographic research was performed on PubMed with the terms intra-abdominal pressure, abdominal compartment syndrome, intracranial pressure, intracranial hypertension. Altogether, 146 articles were observed, 87 of which were from the year 2000, and only 15 articles were considered relevant to the topic. These studies indicate that patients with refractory intracranial hypertension can benefit fromthe measurement of intraabdominal pressure, since there is evidence that an increase in this pressure leads to organic dysfunctions with an indirect impact on cerebral venous return and, consequently, an increase in intracranial pressure. In thosewho underwent decompression laparotomy, direct effectswere observed in reducing intracranial hypertension and survival.

Effect of moderate elevated intra-abdominal pressure on lung mechanics and histological lung injury at different positive end-expiratory pressures.

INTRODUCTION: Intra-abdominal hypertension (IAH) is a well-known phenomenon in critically ill patients. Effects of a moderately elevated intra-abdominal pressure (IAP) on lung mechanics are still not fully analyzed. Moreover, the optimal positive end-expiratory pressure (PEEP) in elevated IAP is unclear. METHODS: We investigated changes in lung mechanics and transformation in histological lung patterns using three different PEEP levels in eighteen deeply anesthetized pigs with an IAP of 10 mmHg. After establishing the intra-abdominal pressure, we randomized the animals into 3 groups. Each of n = 6 (Group A = PEEP 5, B = PEEP 10 and C = PEEP 15 cmH2O). End-expiratory lung volume (EELV/kg body weight (bw)), pulmonary compliance (Cstat), driving pressure (ΔP) and transpulmonary pressure (ΔPL) were measured for 6 hours. Additionally, the histological lung injury score was calculated. RESULTS: Comparing hours 0 and 6 in group A, there was a decrease of EELV/kg (27±2 vs. 16±1 ml/kg; p<0.05) and of Cstat (42±2 vs. 27±1 ml/cmH2O; p<0.05) and an increase of ΔP (11±0 vs. 17±1 cmH2O; p<0.05) and ΔPL (6±0 vs. 10±1 cmH2O; p<0.05). In group B, there was no significant change in EELV/kg (27±3 vs. 24±3 ml/kg), but a decrease in Cstat (42±3 vs. 32±1 ml/cmH20; p<0.05) and an increase in ΔP (11±1 vs. 15±1 cmH2O; p<0.05) and ΔPL (5±1 vs. 7±0 cmH2O; p<0.05). In group C, there were no significant changes in EELV/kg (27±2 vs. 29±3 ml/kg), ΔP (10±1 vs. 12±1 cmH2O) and ΔPL (5±1 vs. 7±1 cmH2O), but a significant decrease of Cstat (43±1 vs. 37±1 ml/cmH2O; p<0.05). Histological lung injury score was lowest in group B. CONCLUSIONS: A moderate elevated IAP of 10 mmHg leads to relevant changes in lung mechanics during mechanical ventilation. In our study, a PEEP of 10 cmH2O was associated with a lower lung injury score and was able to overcome the IAP induced alterations of EELV.

Basic Fibroblast Growth Factor (bFGF) Protects the Blood-Brain Barrier by Binding of FGFR1 and Activating the ERK Signaling Pathway After Intra-Abdominal Hypertension and Traumatic Brain Injury.

BACKGROUND Intra-abdominal hypertension (IAH) is associated with high morbidity and mortality. IAH leads to intra-abdominal tissue damage and causes dysfunction in distal organs such as the brain. The effect of a combined injury due to IAH and traumatic brain injury (TBI) on the integrity of the blood-brain barrier (BBB) has not been investigated. MATERIAL AND METHODS Intracranial pressure (ICP) monitoring, brain water content, EB permeability detection, immunofluorescence staining, real-time PCR, and Western blot analysis were used to examine the effects of IAH and TBI on the BBB in rats, and to characterize the protective effects of basic fibroblast growth factor (bFGF) on combined injury-induced BBB damage. RESULTS Combined injury from IAH and TBI to the BBB resulted in brain edema and increased intracranial pressure. The effects of bFGF on alleviating the rat BBB injuries were determined, indicating that bFGF regulated the expression levels of the tight junction (TJ), adhesion junction (AJ), matrix metalloproteinase (MMP), and IL-1ß, as well as reduced BBB permeability, brain edema, and intracranial pressure. Moreover, the FGFR1 antagonist PD 173074 and the ERK antagonist PD 98059 decreased the protective effects of bFGF. CONCLUSIONS bFGF effectively protected the BBB from damage caused by combined injury from IAH and TBI, and binding of FGFR1 and activation of the ERK signaling pathway was involved in these effects.

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.

The Cushing reflex and the vasopressin-mediated hemodynamic response to increased intracranial pressure during acute elevations in intraabdominal pressure.

BACKGROUND: Abdominal compartment syndrome has been linked to detrimental hemodynamic side effects that include increased intracranial pressure and diminished renal function, but the mechanisms behind this continue to be elucidated. In this study, we sought to investigate any direct association between acute elevations in intra-abdominal pressure and intracranial hypertension during experimentally induced abdominal compartment syndrome and between acutely elevated intracranial pressure and the hemodynamic response that might be elicited by a vasopressin-induced Cushing reflex affecting urine osmolality and urine output. The aim of this study is to explain the Cushing reflex and the vasopressin-mediated hemodynamic response to intracranial pressure during acute elevations in intra-abdominal pressure. METHODS: We measured intra-abdominal pressure, intrathoracic pressure, optic nerve sheath diameter as an indirect sign of intracranial pressure, vasopressin levels in blood, urine osmolality, and urine output at 4 time points during surgery in 16 patients undergoing sleeve gastrectomy for morbid obesity. Values for the 4 time points were compared by repeated-measures analysis of variance. RESULTS: More than 50-fold elevations in serum vasopressin paralleled increases in optic nerve sheath diameter, rising throughout prepneumoperitoneum and tapering off afterward, in conjunction with a marked decrease in urine but not serum osmolality. Mean arterial pressure rose transiently during pneumoperitoneum without elevated positive end-expiratory pressure but was not significantly elevated thereafter. CONCLUSIONS: These findings support our hypothesis that the oliguric response observed in abdominal compartment syndrome might be the result of the acutely elevated intra-abdominal pressure triggering increased intrathoracic pressure, decreased venous outflow from the central nervous system, increased intracranial pressure, and resultant vasopressin release via a Cushing reflex.

First Report of Fatal Secondary Abdominal Compartment Syndrome Induced by Intestinal Gas Accumulation without Organic Occlusive Intestinal Lesion in a Child with Sepsis.

BACKGROUND Abdominal compartment syndrome (ACS), characterized by an increased intra-abdominal pressure and new-onset organ dysfunction, is a critical and potentially fatal condition, with no case of ACS caused by intestinal gas without intestinal lesion being reported to date. CASE REPORT A 2-year-old girl with a chromosomal abnormality of 1p36 deletion presented with fever and diarrhea following upper-gastrointestinal series for the evaluation of gastroesophageal reflux. After 20 days, she experienced septic shock and multiple-organ failure, accompanied with rapidly growing, severe abdominal distension. A marked increase in the intra-abdominal pressure was indicated by the complete loss of elasticity in the extremely hard and distended abdomen. She died 14 h after the onset of shock. Her autopsy examination revealed extensive pneumonia and excessive intestinal gas, despite no occlusive intestinal lesion present. CONCLUSIONS It is critical to be aware that secondary ACS can occur following sepsis due to the accumulation of extensive intestinal gas, without an occlusive intestinal lesion.

Analyzing the effect of laparoscopy duration time on peroperative gastroesophageal reflux

Background/aim: Intraabdominal pressure (IAP) is one of the main reasons for gastroesophageal reflux (GER). This study investigates whether IAP during laparoscopic surgery leads to GER in a time-dependent manner. Materials and methods: In a laparoscopy model, 15 mmHg IAP was created in 8 Wistar albino rats in the Trendelenburg position (TP). A 5 mm laparotomy was performed in the left lower abdominal region, and a 6 Fr catheter was placed intraabdominally. Air was insufflated into the abdominal cavity, and the pressure was kept constant at 15 mmHg. Esophageal pH alterations were measured by pH sticks for 4 h every 30 min. Results: The basal median esophageal pH value was 9 (8­10), the value after placing the catheter was 9 (7­10) (P = 0.47), and the median pH value after placing the subjects in TP was 9 (8­10) (P = 0.70). In our experimental model, esophageal pH values were found to decrease significantly at the 150th minute in TP and at 15 mmHg IAP (P < 0.05). Two rats died: one at the 120th minute and the other at the 240th minute (P > 0.05) Conclusion: Esophageal pH values decreased and continued to remain low following IAP increase and TP in this experimental rat model. Prolonged laparoscopic procedures can particularly lead to GER that requires instant recognition and rapid and appropriate intervention.

Abdominal compartment syndrome secondary to megarectum and megasigmoid.

A 31-year-old male patient with chronic constipation of unknown aetiology presented emergently with worsening nausea, vomiting and abdominal distension of one week duration. On examination, his abdomen was distended with minimal tenderness. A plain film of the abdomen demonstrated severe faecal loading. The patient was haemodynamically unstable on admission and appeared sick. An urgent CT abdomen and pelvis was conducted showing extensive rectal dilatation and associated proximal colonic stercoral perforation. The patient proceeded straight to theatre for laparotomy as his general condition was deteriorating rapidly. On transfer to the operating table, the patient suffered cardiopulmonary arrest. Resuscitation was immediately commenced. Abdominal compartment syndrome was suspected. Cardiac output was re-established following a midline laparotomy which acted relieve the abdominal pressure. The rectosigmoid faecal content was decompressed via an enterotomy. The perforated segment of transverse colon was resected and an end colostomy fashioned. A year later, the continuity of the bowel was re-established.

Presión intraabdominal y ventilación artificial mecánica. Hospital "Arnaldo Milián Castro". 2014-2015 / Intra-abdominal pressure and mechanical artificial ventilation. Arnaldo Milián Castro Hospital. 2014-2015

Introducción: La cavidad abdominal y la caja torácica se encuentran separadas por el diafragma, por lo que las variaciones en las presiones dentro de una, repercuten sobre las presiones de la otra. La hipertensión intraabdominal es hoy una entidad frecuente en el paciente crítico en el que constituye un factor de riesgo importante de complicaciones y mortalidad, ya que influye sobre órganos y sistemas. Objetivo: Relacionar la presión intraabdominal con presiones de la ventilación artificial mecánica y parámetros de la función respiratoria, cardiovascular y renal. Material y Métodos: Se realizó un estudio descriptivo y prospectivo de la presión intraabdominal en pacientes sometidos a ventilación mecánica, con enfermedades clínicas y quirúrgicas, en las Unidades de Cuidados Intensivos del Hospital Clínico Quirúrgico Arnaldo Milán Castro, durante el período comprendido entre enero 2014 hasta diciembre 2015. Resultados: Los pacientes clínicos con presiones de la vía aérea elevadas mostraron valores más altos de presión intraabdominal, y aquellos pacientes postquirúrgicos que cursaron con niveles altos de presión dentro del abdomen también presentaron los valores más elevados de presión pico y media registradas en el ventilador mecánico. Conclusiones: La tensión arterial media, el ritmo diurético y la saturación periférica de oxígeno disminuyeron, mientras que la presión venosa central, la presión parcial de dióxido de carbono en sangre y la creatinina aumentó ante los aumentos de la presión dentro del abdomen(AU)

Introduction: The abdominal cavity and the thoracic cage are separated by the diaphragm; therefore, the variations in the pressures within one of them have an effect on the pressures of the other. At present, intra-abdominal hypertension is a frequent entity in the critically ill patient, which constitutes an important risk factor for complications and mortality since it influences on different organs and systems. Objective: To relate intra-abdominal pressure with mechanical artificial ventilation pressures and parameters of respiratory, cardiovascular and renal function. Material and Methods: A descriptive prospective study of intra-abdominal pressure was conducted in patients undergoing mechanical ventilation with clinical and surgical diseases in the Intensive Care Units of the Arnaldo Milán Castro Hospital, during the period between January 2014 until December 2015. Results: Clinical patients with high values of airway pressures showed higher values of intra-abdominal pressure, and those post-surgical patients who presented with high levels of pressure inside the abdomen indicated the highest values of peak and average pressure recorded in the mechanical ventilator. Conclusions: Mean arterial pressure, diuretic rate and peripheral oxygen saturation decreased, whereas the central venous pressure, the partial pressure of carbon dioxide in blood, and creatinine increased due to raises in pressure within the abdomen(AU)

Novel technique of temporary abdominal closure with continuous medial fascial traction dynamic for patients with open abdomen.

Open abdomen has been an effective treatment for abdominal catastrophes in trauma and general surgery, is one of the greatest advances in recent decades and has become a common procedure in both trauma and general surgery. Temporary abdominal closure techniques in managing open abdomen help to achieve many benefits without incurring many complications. We present a series of patients in which a temporary abdominal closure technique was used that generates continuous medial fascial traction dynamic in patients with open abdomen for different causes.

The open abdomen in trauma and non-trauma patients: WSES guidelines.

Damage control resuscitation may lead to postoperative intra-abdominal hypertension or abdominal compartment syndrome. These conditions may result in a vicious, self-perpetuating cycle leading to severe physiologic derangements and multiorgan failure unless interrupted by abdominal (surgical or other) decompression. Further, in some clinical situations, the abdomen cannot be closed due to the visceral edema, the inability to control the compelling source of infection or the necessity to re-explore (as a "planned second-look" laparotomy) or complete previously initiated damage control procedures or in cases of abdominal wall disruption. The open abdomen in trauma and non-trauma patients has been proposed to be effective in preventing or treating deranged physiology in patients with severe injuries or critical illness when no other perceived options exist. Its use, however, remains controversial as it is resource consuming and represents a non-anatomic situation with the potential for severe adverse effects. Its use, therefore, should only be considered in patients who would most benefit from it. Abdominal fascia-to-fascia closure should be done as soon as the patient can physiologically tolerate it. All precautions to minimize complications should be implemented.

Damage Control Surgery for Non-traumatic Abdominal Emergencies.

BACKGROUND: Damage control surgery (DCS) was a major paradigm change in the management of critically ill trauma patients and has gradually expanded in the general surgery arena, but data in this setting are still scarce. The study aim was to evaluate outcomes of DCS in patients with general surgery emergencies. METHODS: Between 2005 and 2015, 164 patients (104 men, age 66) underwent DCS for non-traumatic abdominal emergencies. The decision to perform DCS was triggered by the presence of at least one trauma DCS criterion: hypotension (<70 mmHg), hypothermia (<35 °C), acidosis (pH < 7.25), coagulopathy (INR ≥ 1.7) and massive (>5 RBC) transfusion. Statistical tests were performed to identify risk factors for operative mortality. Observed outcomes were compared to those predicted by commonly employed scores (APACHE II, POSSUM, P-POSSUM, SAPS II). RESULTS: DCS was performed for acute mesenteric ischemia (n = 68), peritonitis (n = 44), pancreatitis (n = 28), bleeding (n = 14) and other (n = 10). Abdominal compartment syndrome was associated in 52 patients (32%). Seventy-four (45%) patients died and 150 patients (91%) experienced complications. On multivariate analysis, age (p = 0.018) and INR ≥ 1.7 (p = 0.001) were independent predictors of mortality. Mortality was 24% (13/55), 48% (22/46) and 62% (39/63) in patients with one, two and ≥3 DCS criteria, respectively. Comparison of observed and score-predicted mortality suggested DCS use resulted in significant survival benefit of the whole cohort and of patients with pancreatitis and postoperative peritonitis. CONCLUSIONS: DCS can be lifesaving in critically ill patients with general surgery emergencies. Patients with peritonitis and acute pancreatitis are those who benefit most of the DCS approach.

Risk factors for and the prevention of acute kidney injury after abdominal surgery.

Postoperative acute kidney injury in patients undergoing abdominal surgery is not rare and often results in bad outcomes for patients. The incidence of postoperative acute kidney injury is hard to evaluate reliably due to its non-unified definitions in different studies. Risk factors for acute kidney injury specific to abdominal surgery include preoperative renal insufficiency, intraabdominal hypertension, blood transfusion, bowel preparation, perioperative dehydration, contrast agent and nephrotoxic drug use. Among these, preoperative renal insufficiency is the strongest predictor of acute kidney injury. The peri-operative management of high-risk patients should include meticulous selection of fluid solutions. Balanced crystalloid solutions and albumin are generally thought to be relatively safe, while the safety of hydroxyethyl starch solutions has been controversial. The purpose of the present review is to discuss the current knowledge regarding postoperative acute kidney injury in abdominal surgical settings to help surgeons make better decisions concerning the peri-operative management.

The cardio-respiratory effects of intra-abdominal hypertension: Considerations for critical care nursing practice.

Intra-abdominal hypertension can be classified as either primary or secondary. Primary intra-abdominal hypertension is often associated through trauma or diseases of the abdominopelvic region such as pancreatitis or abdominal surgery, while secondary intra-abdominal hypertension is the result of extra-abdominal causes such as sepsis or burns. The critically ill patient offers some challenges in monitoring in particular secondary intra-abdominal hypertension because of the effects of fluid resuscitation, the use of inotropes and positive pressure ventilation. Recent work suggests that intensive care unit nurses are often unaware of the secondary effects of intra-abdominal pressure and therefore this is not monitored effectively. Therefore being aware of the cardio-respiratory effects may alert theintensive care nurse nurse to the development of intra-abdominal hypertension. The aim of this paper is to discuss the pathophysiology associated with the cardio-respiratory effects seen with intra-abdominal hypertension in the critically ill. In particular it will discuss how intra-abdominal hypertension can inadvertently be overlooked because of the low flow states that it produces which could be misconstrued as something else. It will also discuss how intra-abdominal hypertension impedes ventilation and respiratory mechanics which can often result in a non-cardiogenic pulmonary oedema. To close, the paper will offer some implications for critical care nursing practice.

Valsalva maneuver exacerbates left atrial compression in patients with large hiatal hernia.

INTRODUCTION: Hiatal hernia (HH) can cause left atrial (LA) compression and impair LA filling. We evaluated the cardiac effects of preload reduction and abdominal strain induced by Valsalva maneuver (VM) in large HH patients. METHODS: LA and left ventricular (LV) dimensions were measured using 2D transthoracic echocardiography at rest and during VM in HH patients (n=55, 70±10 years) and controls (n=22, 67±6 years). Biplane LV volumes (n=39) and mitral inflow pulse-wave Doppler parameters (n=27) were also evaluated. In HH patients, resting LA compression was graded qualitatively (none-mild or moderate-severe). RESULTS: In both controls and HH patients, VM significantly decreased LA (controls, 19±2 vs 16±3 mm/m2 ; HH, 16±5 vs 9±5 mm/m2 ) and LV diameters (22±3 vs 19±3 mm/m2 ; 21±3 vs 17±3 mm/m2 ) and LV volume (38±8 vs 26±10 mL/m2 ; 31±8 vs 19±9 mL/m2 ) (P<.001 for all). VM decreased LA diameter significantly more in HH patients than controls (-42% vs -16%, P<.001). HH patients with none-mild resting LA compression exhibited significantly greater LA diameter reduction than controls (-38±23% vs -16±13% P=.0003) despite similar resting LA diameters. LV volumes were similarly decreased by VM in HH patients and controls irrespective of resting LA compression severity indicating relative preservation of LV filling. LA diameter correlated inversely with early diastolic filling velocity during VM in HH patients (R=-.43, P=.03) but not controls (R=.18, P=.43). CONCLUSION: VM can markedly exacerbate LA compression in HH patients; however, LV filling is relatively less affected possibly due to augmented early diastolic filling. Conditions associated with decreased preload and increased intra-abdominal pressure may exacerbate the cardiac effects of large HH.