Surgical Critical Care

Medical School · Year 4 · Subinternship Surgery · includes a quiz and discussion video

Surgical Critical Care

Year 4: Sub-Internship Surgery

Learning Objectives

By the end of this seminar, students will be able to:

Apply principles of hemodynamic resuscitation including fluid management and vasopressor selection
Manage basic mechanical ventilation settings and recognize common ventilator problems
Recognize and implement the sepsis bundle for surgical patients with infection
Apply evidence-based nutritional support principles for critically ill surgical patients
Manage sedation and analgesia in the ICU using validated assessment tools and protocols
Participate effectively in ICU rounds using systematic organ-based presentation and daily checklists

Section I: Hemodynamic Resuscitation

Hemodynamic goals in the critically ill surgical patient target restoration of adequate tissue perfusion. Mean arterial pressure greater than sixty-five mmHg provides sufficient driving pressure for organ perfusion in most patients, though some may require higher targets. Urine output exceeding half a milliliter per kilogram per hour indicates adequate renal perfusion. Lactate clearance, reflecting resolution of anaerobic metabolism, serves as a dynamic marker of resuscitation adequacy; decreasing lactate with treatment indicates improving perfusion. Central venous oxygen saturation above seventy percent suggests adequate oxygen delivery relative to consumption. Mental status improvement reflects cerebral perfusion. These targets guide resuscitation intensity without being absolute thresholds.

Fluid resuscitation addresses hypovolemia and optimizes preload to maximize cardiac output. Crystalloid solutions, particularly lactated Ringer's solution or normal saline, serve as first-line resuscitation fluids. Initial volume of thirty milliliters per kilogram is recommended for sepsis, though response should guide subsequent administration. Albumin may be considered in patients requiring large-volume resuscitation or with significant hypoalbuminemia. Blood products are indicated for hemorrhage or significant anemia affecting oxygen delivery. Excessive crystalloid administration causes tissue edema, respiratory compromise, and abdominal compartment syndrome; resuscitation must balance volume needs against fluid overload risks.

Vasopressor selection depends on the hemodynamic profile and underlying cause of shock. Norepinephrine serves as the first-line vasopressor for septic shock, providing potent alpha-adrenergic vasoconstriction with some beta-adrenergic cardiac support. Vasopressin acts through V1 receptors independent of catecholamine pathways and is added when norepinephrine alone is insufficient. Epinephrine provides balanced alpha and beta effects and is preferred for anaphylaxis and as an adjunct in septic shock. Phenylephrine, a pure alpha agonist, suits situations where vasoconstriction is needed without cardiac stimulation. Dobutamine, a beta-1 agonist, augments cardiac contractility and is added when cardiac output is inadequate despite adequate filling pressures.

Hemodynamic monitoring guides resuscitation decisions. Arterial line placement provides continuous blood pressure measurement and access for frequent blood gas sampling. Central venous access enables vasopressor administration and central venous pressure monitoring, though CVP has limited utility for guiding fluid responsiveness. Pulse contour analysis from arterial waveforms provides continuous cardiac output estimation in some systems. Point-of-care ultrasound assesses cardiac function, inferior vena cava diameter, and fluid responsiveness non-invasively. Pulmonary artery catheters, though rarely used, provide detailed hemodynamic profiles when needed. The trend of parameters over time provides more useful information than single measurements.

Section II: Mechanical Ventilation

Indications for mechanical ventilation include both respiratory failure and other conditions requiring airway protection. Hypoxemic respiratory failure, with PaO2 below sixty mmHg despite supplemental oxygen, requires ventilatory support. Hypercapnic respiratory failure with rising PCO2 and acidosis indicates inadequate ventilation. Airway protection becomes necessary when decreased consciousness impairs reflexes, putting patients at aspiration risk. High work of breathing unsustainable by the patient warrants support even before frank failure develops. Post-operative ventilation following complex surgery allows controlled emergence and assessment. Shock states benefit from reduced oxygen demand when respiratory muscles are supported mechanically.

Basic ventilator modes provide different levels of support and patient interaction. Volume-controlled ventilation delivers a set tidal volume with each breath, with airway pressure varying based on compliance and resistance. Pressure-controlled ventilation delivers a set pressure with each breath, with tidal volume varying based on compliance. Assist-control modes provide full support for each breath, whether triggered by the patient or the ventilator. Synchronized intermittent mandatory ventilation (SIMV) allows spontaneous breathing between mandatory breaths. Pressure support provides a set pressure boost during patient-initiated breaths, commonly used for weaning. Mode selection depends on the clinical situation, institutional preference, and patient needs.

Initial ventilator settings establish baseline support that is then titrated to patient response. FiO2 typically starts at one hundred percent and is rapidly weaned to maintain oxygen saturation above ninety-two percent. Tidal volume of six to eight milliliters per kilogram of ideal body weight provides adequate ventilation while limiting barotrauma. Respiratory rate of twelve to sixteen breaths per minute is adjusted based on pH and PCO2. Positive end-expiratory pressure (PEEP) of five to eight centimeters of water maintains alveolar recruitment. Plateau pressure is monitored with goal below thirty centimeters of water to prevent ventilator-induced lung injury. Settings are adjusted based on arterial blood gas results and clinical assessment.

Troubleshooting ventilator problems follows a systematic approach. High peak pressures suggest increased resistance from bronchospasm, mucus plugging, or kinked endotracheal tube. High plateau pressures indicate decreased compliance from pulmonary edema, pneumothorax, or abdominal distension. Hypoxia despite adequate FiO2 and PEEP prompts assessment for pneumothorax, mucus plugging, pulmonary embolism, or worsening primary lung disease. Hypercapnia responds to increased minute ventilation through higher rate or tidal volume. Patient-ventilator dyssynchrony, with the patient fighting the ventilator, may require sedation adjustment or mode change. When in doubt, disconnecting from the ventilator and hand-ventilating simplifies assessment while basic problems are excluded.

Section III: ARDS Management

The Berlin definition of acute respiratory distress syndrome establishes diagnostic criteria for this severe lung injury. Timing requires onset within one week of a known clinical insult or new or worsening respiratory symptoms. Imaging demonstrates bilateral opacities on chest radiograph or CT not fully explained by effusions, nodules, or lobar collapse. Origin requires that respiratory failure not be fully explained by cardiac failure or fluid overload; echocardiography may be needed to exclude cardiogenic edema. Severity is classified by PaO2/FiO2 ratio with PEEP greater than or equal to five: mild is 200-300, moderate is 100-200, and severe is less than 100. These criteria standardize diagnosis and enable comparison across studies and institutions.

Lung-protective ventilation represents the cornerstone of ARDS management, reducing ventilator-induced lung injury that worsens outcomes. Low tidal volume of six milliliters per kilogram of ideal body weight, lower than traditionally used volumes, reduces alveolar overdistension. Plateau pressure target below thirty centimeters of water limits transpulmonary pressure. Higher PEEP, titrated using standardized tables or individualized approaches, maintains alveolar recruitment in heterogeneous lung injury. Permissive hypercapnia accepts elevated PCO2 and mild acidosis (pH greater than 7.20) rather than increasing tidal volumes that would cause lung injury. These principles, established by the ARDS Network trials, significantly improved survival.

Additional interventions benefit selected ARDS patients. Prone positioning for patients with PaO2/FiO2 less than 150 improves oxygenation through redistribution of ventilation and perfusion and reduces mortality. Sessions of twelve to sixteen hours are typically employed. Neuromuscular blockade may improve synchrony and oxygenation in early severe ARDS, though recent trials question routine use. Conservative fluid management after initial resuscitation reduces pulmonary edema without compromising organ perfusion. Extracorporeal membrane oxygenation (ECMO) provides oxygenation and CO2 removal for the most severe refractory cases at experienced centers. Corticosteroids may benefit some patients with prolonged ARDS, though evidence remains evolving.

Prevention strategies reduce ARDS incidence in at-risk patients. Lung-protective ventilation principles apply to all mechanically ventilated patients, not only those with established ARDS. Aspiration precautions including head of bed elevation and oral care reduce one common trigger. Early recognition of at-risk patients, such as those with severe pneumonia, sepsis, or aspiration, allows close monitoring. Treating underlying conditions, including pneumonia and sepsis, addresses the inciting insult. Judicious fluid resuscitation avoids unnecessary volume loading. When ARDS develops despite prevention efforts, early implementation of lung-protective strategies limits progression.

Section IV: Sepsis Management

Sepsis recognition requires systematic screening and rapid clinical assessment. qSOFA (quick Sequential Organ Failure Assessment) screens for patients outside the ICU with respiratory rate greater than or equal to twenty-two, altered mental status, or systolic blood pressure less than or equal to one hundred; two or more criteria suggest sepsis and warrant further evaluation. SOFA score quantifies organ dysfunction across respiratory, coagulation, liver, cardiovascular, neurologic, and renal systems. Septic shock is defined as sepsis with lactate greater than two despite adequate fluid resuscitation and need for vasopressors to maintain MAP greater than or equal to sixty-five. In surgical patients, source consideration includes wound infection, anastomotic leak, abscess, infected prosthetic material, and device-related infection.

The sepsis bundle codifies time-sensitive interventions that improve outcomes. Within one hour of recognition, lactate should be measured to assess tissue perfusion. Blood cultures should be obtained before antibiotics when possible but should not delay antibiotic administration. Broad-spectrum antibiotics covering likely pathogens should be administered. Crystalloid resuscitation of thirty milliliters per kilogram should begin for hypotension or lactate greater than four. Vasopressors should start if hypotension persists despite fluid resuscitation. While specific timing targets remain debated, the principle of rapid, aggressive intervention is well-established.

Source control addresses the underlying cause of surgical sepsis and often determines outcome. Drainage of abscess, whether percutaneous or surgical, removes the infection reservoir. Debridement of infected or necrotic tissue eliminates the ongoing sepsis source. Repair or resection of anastomotic leak addresses ongoing contamination. Removal of infected prosthetic material, including lines, drains, and implants, may be necessary despite the associated morbidity. Timing of source control should occur within six to twelve hours of identification when feasible. Antibiotic therapy alone cannot overcome inadequate source control; the two must work together.

Ongoing sepsis management supports organ function while the infection is treated. Antibiotic de-escalation narrows coverage based on culture results, typically within forty-eight to seventy-two hours. Duration of antibiotics is typically seven to ten days but should be individualized. Stress-dose steroids (hydrocortisone two hundred milligrams daily) are considered for shock refractory to fluids and vasopressors, though evidence remains mixed. Glycemic control targeting less than one hundred eighty milligrams per deciliter reduces complications without the risks of tight control. Deep venous thrombosis and stress ulcer prophylaxis continue. Nutritional support, preferably enteral, maintains gut integrity and immune function.

Section V: Nutritional Support

Route selection prioritizes enteral nutrition when the gut is functional. The principle "if the gut works, use it" reflects evidence that enteral feeding maintains mucosal integrity, supports immune function, and reduces infectious complications compared to parenteral nutrition. Early enteral nutrition, initiated within twenty-four to forty-eight hours of ICU admission, provides benefits even at low feeding rates. Gastric feeding represents the default approach, with most patients tolerating gastric delivery. Post-pyloric feeding, with tube tip beyond the pylorus, benefits patients with gastroparesis, high aspiration risk, or gastric feeding intolerance. Parenteral nutrition is reserved for patients in whom enteral nutrition is contraindicated or cannot meet needs.

Enteral nutrition implementation requires appropriate access and monitoring. Nasogastric tubes provide gastric access for short-term feeding. Nasoduodenal or nasojejunal tubes, often placed with fluoroscopic or endoscopic guidance, provide post-pyloric access. Gastrostomy and jejunostomy tubes provide long-term access when prolonged tube feeding is anticipated. Standard polymeric formulas suit most patients; disease-specific formulas exist for renal failure, hepatic failure, and diabetes but are not universally superior. Trophic or trickle feeds at low rates provide gut mucosal benefits while avoiding complications; advancement to goal follows tolerance assessment.

Parenteral nutrition addresses nutritional needs when the gut cannot be used. Indications include mechanical obstruction without surgical bypass, severe malabsorption, high-output fistula, and early severe pancreatitis. Access typically requires central venous catheter due to the hyperosmolar nature of concentrated solutions. Composition includes dextrose for calories, amino acids for protein, and lipid emulsion for essential fatty acids and additional calories. Electrolytes, vitamins, and trace elements are added. Careful monitoring of glucose, electrolytes, and liver function guides adjustments. Complications include hyperglycemia, electrolyte disturbances, and hepatic steatosis with prolonged use.

Monitoring nutritional therapy ensures adequacy and prevents complications. Caloric goals of twenty-five to thirty kilocalories per kilogram per day maintain metabolic needs, with adjustment for obesity and critical illness phases. Protein goals of 1.2 to 2.0 grams per kilogram per day support tissue repair and immune function. Gastric residual volumes, though controversial, help assess feeding tolerance; volumes less than 500 milliliters generally allow continued feeding. Glucose monitoring prevents hyperglycemia, with insulin used to maintain levels below one hundred eighty milligrams per deciliter. Electrolyte monitoring, including phosphorus during refeeding, guides supplementation. Weight trends and nitrogen balance provide longer-term adequacy assessment.

Section VI: Sedation and Analgesia

Pain assessment in the critically ill requires tools appropriate for communication ability. Numeric rating scales (zero to ten) remain the gold standard for patients who can communicate. The Behavioral Pain Scale (BPS) assesses facial expression, upper limb movement, and compliance with ventilation in non-communicative patients. The Critical-Care Pain Observation Tool (CPOT) similarly uses behavioral indicators including facial expression, body movements, muscle tension, and vocalization or ventilator compliance. Physiologic signs such as tachycardia and hypertension suggest pain but are non-specific. Regular assessment, at least every four hours and before and after interventions, enables appropriate treatment.

Analgesic selection balances efficacy, side effects, and patient characteristics. Fentanyl provides rapid onset and short duration, making it suitable for titration; it also lacks active metabolites, advantageous in renal impairment. Hydromorphone offers longer duration than fentanyl with favorable renal profile. Morphine is effective but has active metabolites that accumulate in renal failure. Non-opioid adjuncts including acetaminophen and, when not contraindicated, NSAIDs reduce opioid requirements. Ketamine provides analgesia with bronchodilation and preserved hemodynamics. Regional analgesia techniques, when applicable, provide excellent pain control without systemic effects.

Sedation goals typically target light sedation that preserves patient comfort while allowing assessment and interaction. The Richmond Agitation-Sedation Scale (RASS) provides validated sedation assessment, ranging from plus four (combative) through zero (alert and calm) to minus five (unarousable). Target sedation level is typically RASS zero to minus two (calm to lightly sedated). Propofol offers rapid onset and offset, facilitating daily awakening trials, but can cause hypotension and propofol infusion syndrome with prolonged high-dose use. Dexmedetomidine provides sedation without respiratory depression and may reduce delirium risk. Benzodiazepines, particularly midazolam, are less preferred due to accumulation and delirium association but remain useful for alcohol withdrawal and specific situations.

Daily awakening trials improve outcomes and should be standard practice. Sedation is held each morning to assess neurologic status and spontaneous breathing potential. Patients reaching light sedation or awakening undergo spontaneous breathing trials if criteria are met. Combined sedation and breathing trials reduce ventilator days and ICU length of stay. Staff should be at bedside during awakening to ensure safety and provide reassurance. Delirium screening using validated tools such as CAM-ICU should occur during awakening. Resumption of sedation at reduced doses follows trial completion, with reassessment of ongoing sedation needs.

Section VII: ICU Complications

Bleeding in the surgical ICU requires systematic evaluation and intervention. Surgical site bleeding may indicate inadequate intraoperative hemostasis, coagulopathy, or medication effect. Stress ulcer prophylaxis with proton pump inhibitors or H2 receptor blockers reduces gastrointestinal bleeding risk in ICU patients. Coagulopathy from sepsis, liver dysfunction, or dilution requires factor replacement with fresh frozen plasma, cryoprecipitate, or specific factors. Thrombocytopenia may result from sepsis, medication effect, or heparin-induced thrombocytopenia. Assessment includes review of hemoglobin trends, examination of surgical sites, evaluation of drains, and coagulation studies. Management addresses both the bleeding source and any underlying coagulation abnormality.

Nosocomial infections complicate ICU stays and increase mortality. Ventilator-associated pneumonia prevention bundles include head of bed elevation, daily awakening trials, oral care, and assessment of readiness for extubation. Central line-associated bloodstream infection prevention requires hand hygiene, maximal barrier precautions during insertion, chlorhexidine skin preparation, optimal site selection (avoiding femoral), and daily review of line necessity. Catheter-associated urinary tract infection prevention focuses on avoiding unnecessary catheterization, using aseptic insertion technique, maintaining closed drainage systems, and removing catheters as soon as possible. Compliance with bundles dramatically reduces infection rates.

Delirium affects a majority of ICU patients and worsens outcomes. Risk factors include advanced age, baseline cognitive impairment, severity of illness, sedative medications (particularly benzodiazepines), and sleep disruption. Screening with validated tools such as the Confusion Assessment Method for the ICU (CAM-ICU) should occur at least once per shift. Prevention strategies include early mobilization, sleep hygiene with reduced nighttime interruptions, orientation efforts, hearing aid and glasses provision, and sedation minimization. Pharmacologic prevention with haloperidol or atypical antipsychotics lacks strong evidence. Treatment addresses underlying causes and uses antipsychotics for severe agitation while avoiding physical restraints when possible.

ICU-acquired weakness results from both critical illness myopathy and polyneuropathy. Risk factors include prolonged immobility, corticosteroid use, neuromuscular blocking agents, and severe sepsis. Prevention through early mobility programs reduces weakness incidence and improves functional outcomes. Physical therapy consultation early in the ICU stay establishes mobility progression. Progressive mobilization from passive range of motion through sitting, standing, and ambulation occurs as patient condition permits. Occupational therapy addresses functional activities. Even intubated and mechanically ventilated patients can participate in mobility with appropriate support and monitoring.

Section VIII: Hemodynamic Monitoring

Invasive monitoring provides continuous, precise hemodynamic data in unstable patients. Arterial catheter placement, typically radial, provides continuous blood pressure waveform and access for frequent blood gas sampling. Central venous catheter placement enables central venous pressure measurement, though CVP poorly predicts fluid responsiveness. The central venous waveform provides information about cardiac rhythm and right heart function. Pulmonary artery catheters, though rarely used currently, measure pulmonary artery pressures, pulmonary capillary wedge pressure, and cardiac output. Pulse contour analysis systems estimate cardiac output continuously from arterial waveform. Each device has specific indications, complications, and interpretation requirements.

Non-invasive assessment complements or replaces invasive monitoring in appropriate settings. Point-of-care ultrasound provides rapid bedside evaluation of cardiac function, volume status, and specific pathology. Echocardiography assesses ejection fraction, wall motion abnormalities, valvular function, and pericardial effusion. Inferior vena cava diameter and collapsibility indicate volume status and fluid responsiveness. Lung ultrasound identifies pulmonary edema, consolidation, and pleural effusion. Passive leg raising with stroke volume monitoring predicts fluid responsiveness better than static measures. These tools enable rapid, repeatable assessment without the risks of invasive devices.

Shock differentiation guides appropriate hemodynamic management. Hypovolemic shock presents with low central venous pressure, low cardiac output, and high systemic vascular resistance; treatment is volume replacement. Cardiogenic shock presents with elevated filling pressures, low cardiac output, and high resistance; treatment addresses the cardiac cause while supporting with inotropes. Distributive shock (sepsis, anaphylaxis) presents with low vascular resistance, often elevated cardiac output, and variable filling pressures; treatment includes vasopressors and addressing the underlying cause. Obstructive shock (tension pneumothorax, tamponade, massive PE) presents with elevated filling pressures, low cardiac output, and variable resistance; treatment is relieving the obstruction.

Goal-directed therapy targets specific hemodynamic endpoints. Mean arterial pressure above sixty-five mmHg ensures adequate perfusion pressure for most patients; higher targets may benefit those with chronic hypertension. Lactate clearance of ten percent per hour indicates improving tissue perfusion; persistent elevation prompts reassessment. Urine output exceeding half a milliliter per kilogram per hour suggests adequate renal perfusion. Mental status improvement reflects cerebral perfusion. Dynamic measures such as pulse pressure variation or stroke volume variation guide fluid responsiveness better than static pressures. Endpoints are guides, not absolute targets; clinical judgment integrates multiple parameters.

Section IX: Weaning and Extubation

Readiness assessment identifies patients prepared for liberation from mechanical ventilation. Oxygenation criteria include FiO2 less than or equal to forty percent and PEEP less than or equal to eight centimeters of water with adequate saturation. Hemodynamic stability without high-dose vasopressors or active ischemia is required. Neurologic status should demonstrate adequate alertness to follow commands and protect the airway. Adequate cough strength enables secretion clearance. Secretion volume should be manageable without continuous suctioning. Underlying indication for ventilation should be resolving or resolved. Daily screening against these criteria identifies extubation candidates.

The spontaneous breathing trial (SBT) tests the patient's ability to breathe without full ventilator support. Methods include T-piece breathing (disconnected from ventilator), low-level pressure support (five to eight centimeters of water), or CPAP alone. Trial duration of thirty to one hundred twenty minutes allows assessment of sustainability. Success criteria include stable respiratory rate (less than thirty-five breaths per minute), adequate tidal volume, acceptable oxygen saturation, stable heart rate and blood pressure, and patient comfort. Failure is indicated by tachypnea, desaturation, tachycardia, hypertension or hypotension, anxiety, or diaphoresis. Failed trials prompt evaluation of the cause before reattempting.

Extubation follows successful SBT with additional assessments. Cuff leak test, deflating the endotracheal tube cuff to assess air movement around the tube, may predict post-extubation stridor from airway edema; its routine use remains debated. Airway patency should be ensured without anatomic obstruction. Patient should be able to follow commands and protect the airway. Secretions should be suctioned and manageable. Emergency reintubation equipment should be available. Following extubation, oxygen is provided as needed and the patient is monitored for respiratory distress.

Reintubation, required in approximately fifteen percent of patients, indicates either premature extubation or new complications. Post-extubation stridor from laryngeal edema may respond to racemic epinephrine nebulization or dexamethasone; severe cases require reintubation. Respiratory failure from inadequate cough, secretion retention, or respiratory muscle fatigue necessitates ventilatory support. Airway obstruction from secretions or laryngospasm requires immediate intervention. Aspiration in patients with inadequate airway protection prompts reintubation. Identifying reintubation risk factors before extubation allows appropriate monitoring intensity and potential preventive interventions.

Section X: ICU Rounds and Documentation

Structured ICU rounds ensure comprehensive patient assessment and team communication. Overnight events, including vital sign changes, interventions, and nursing concerns, begin the presentation. Current status provides vital signs, ventilator settings, vasoactive medications, and physical examination findings. Systematic organ-by-system review addresses neurologic, cardiovascular, respiratory, gastrointestinal, renal, infectious, hematologic, and endocrine status. Laboratory and imaging results are presented with interpretation. Assessment synthesizes the clinical picture. The plan addresses each active issue with specific actions. Daily goals clarify priorities and expected milestones. This systematic approach prevents omissions and ensures comprehensive care.

Daily checklists complement rounds by ensuring evidence-based interventions are addressed. Sedation assessment asks whether sedation can be reduced or held for an awakening trial. Spontaneous breathing trial readiness is evaluated for ventilated patients. DVT prophylaxis adequacy is confirmed. Stress ulcer prophylaxis appropriateness is assessed, recognizing that not all patients require it. Head of bed elevation is verified for aspiration prevention. Line necessity is reviewed, with removal of unnecessary central lines, arterial lines, and urinary catheters. Nutrition status confirms that enteral feeding is progressing or parenteral nutrition is appropriately indicated. Checklists reduce preventable complications and length of stay.

Family communication maintains relationships and supports shared decision-making. Daily updates provide consistent information from the primary team, preventing confusion from multiple sources. Family meetings address major decisions, prognosis discussions, and care planning. Goals of care conversations, particularly for patients with poor prognosis, clarify values and guide treatment intensity. Questions are answered honestly with acknowledgment of uncertainty when appropriate. Social work and chaplaincy support addresses psychosocial and spiritual needs. Written materials supplement verbal communication for complex information. Compassionate, honest communication builds trust and supports families through difficult times.

Transitions of care represent vulnerable periods requiring thorough handoff. ICU to floor transfer requires detailed communication of active issues, medication changes, monitoring needs, and signs of deterioration that should prompt notification. Night shift handoff conveys overnight concerns, pending tasks, and contingency plans. Service-to-service transitions, such as transfer from surgical to medical ICU, require complete transfer of information and responsibility. Pending results and follow-up items must be explicitly communicated with responsibility clearly assigned. Standardized handoff tools improve information transfer and reduce errors during these transitions.

Summary

Surgical critical care requires systematic approach to complex, rapidly evolving patients. Hemodynamic resuscitation targets MAP greater than sixty-five, lactate clearance, and adequate urine output using fluids and vasopressors selected for the shock type: norepinephrine for septic shock, fluids for hypovolemia, and inotropes for cardiogenic failure. Mechanical ventilation follows lung-protective principles with tidal volumes of six to eight milliliters per kilogram, plateau pressure below thirty, and mode selection based on patient needs; ARDS management intensifies these principles with prone positioning for severe hypoxemia. Sepsis management implements the one-hour bundle of lactate, cultures, antibiotics, fluids, and vasopressors while pursuing surgical source control through drainage, debridement, or repair. Nutritional support preferentially uses enteral nutrition starting within twenty-four to forty-eight hours, reserving parenteral nutrition for non-functional gut. Sedation and analgesia use validated tools for assessment, target light sedation with daily awakening trials, and employ analgesia-first approaches. ICU complications including bleeding, nosocomial infection, delirium, and weakness are prevented through evidence-based bundles. Hemodynamic monitoring combines invasive devices with point-of-care ultrasound to differentiate shock types and guide therapy. Weaning follows daily readiness assessment, spontaneous breathing trials, and careful extubation with reintubation resources available. ICU rounds use systematic organ-based presentation with daily checklists, supported by regular family communication and thorough transition handoffs.

Key Terms

MAP (Mean Arterial Pressure): Primary target for hemodynamic resuscitation, calculated as diastolic pressure plus one-third of pulse pressure; goal typically greater than sixty-five mmHg.

ScvO2 (Central Venous Oxygen Saturation): Marker of oxygen delivery-consumption balance; values above seventy percent suggest adequate delivery relative to demand.

ARDS (Acute Respiratory Distress Syndrome): Severe lung injury characterized by bilateral infiltrates, hypoxemia (P/F ratio less than 300), and non-cardiogenic edema, requiring lung-protective ventilation.

Lung-Protective Ventilation: Strategy using low tidal volumes and limiting plateau pressure to reduce ventilator-induced lung injury.

SBT (Spontaneous Breathing Trial): Test of patient's ability to breathe with minimal ventilator support, used to assess readiness for extubation.

VAP (Ventilator-Associated Pneumonia): Pneumonia developing after forty-eight hours of mechanical ventilation, preventable through evidence-based bundles.

CLABSI (Central Line-Associated Bloodstream Infection): Bloodstream infection attributable to central venous catheter, reduced through insertion and maintenance bundles.

ICU-AW (ICU-Acquired Weakness): Neuromuscular dysfunction developing during critical illness, prevented through early mobilization and medication minimization.

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