Chapter 6
Early Identification of Complications

Even great clinicians make mistakes. What sets a high-value clinician apart is humility: the ability to recognize errors early and take appropriate corrective action. In contrast, low-value clinicians often miss complications and double down on misguided decisions. You will encounter complications in your career, and thankfully, most will not lead to meaningful harm. Egregious errors often follow a familiar pattern: a clinician overlooks a developing issue, fails to reassess, and attributes clinical deterioration to a series of unrelated events rather than recognizing a single mistake that is escalating into a critical problem.

First, study up on procedures. In our field, even a small mistake early in a procedure can have exponentially harmful consequences. You may not encounter every vascular access or airway complication during training, which makes studying them all the more essential. Complications lurk just beneath the surface of everything we do: from relatively minor issues like ocular or dental injury, uvular bruising, and jaw dislocation, to severe and potentially life-threatening events such as postoperative blindness, vocal cord damage, tracheal tears, inadvertent arterial cannulation, or medication errors. Start off on the right foot by learning procedural technique correctly from the outset. Read ahead about the preparation and management of complications. Reading additionally helps you debunk common procedural myths (i.e., the Allen test) and prevents you from picking up bad habits.

Second, learn from complications and ask questions. For instance, if you hear about a central line placed into a nonvascular structure, dig into the details: Was ultrasound used? Were there early warning signs that were missed? How was placement confirmed? What actions were taken once the error was recognized? Was help called promptly? As lifelong learners, we should regularly review compelling cases to deepen our understanding and improve our practice.

Finally, be humble and ask for help. Overconfidence is dangerous, while thoughtful second-guessing is a strength. There is no clinical scenario in which seeking input from a colleague is inappropriate. Doing so never makes you look weak. On the contrary, it reflects sound judgment and maturity.

Your primary responsibility as a trainee isn’t to be perfect on the first try, but to avoid causing harm. I emphasize this to every trainee: if you feel resistance, stop. If you’re unsure, ask. We get into serious trouble when we blindly push ahead just to “get it done” instead of recognizing when to pause and reassess. Let me be clear: there is no procedure in anesthesia that requires brute force. If you’re forcing it, you’re doing it wrong!

Identification of problems requires vigilance. Alarm hygiene is critical for this very reason. You may assume that as a 1:1 provider, nothing will escape your notice. This is an assumption that will prove itself wrong time and time again. Overly sensitive alarms can lead to “alarm fatigue,” in which you miss sustained loss in ETCO₂ while you are troubleshooting a positioning issue after induction. Overly lax alarms can lead to you missing a critical cardiac event while you are troubleshooting a respiratory one.

Before your first case in any OR, I recommend reviewing the default alarm settings on both the ventilator and vital sign monitor. This gives you a sense of what the machine considers important and lets you compare that to your own clinical priorities. As you gain experience over a few months, consider customizing alarm thresholds so you’re only alerted to values that actually warrant your attention.

Personally, I disable systolic and diastolic pressure alarms but maintain a MAP alarm set to 65 or 70. This keeps me disciplined about maintaining safe perfusion without being inundated by alarms. I also set the oxygen saturation alarm to 80, since the tonal changes in the pulse oximeter waveform are often more informative than an arbitrary cutoff.

Ventilator alarms in particular always deserve your attention. This is the most critical advice I give residents: if a vent alarm goes off, stop what you’re doing and assess the situation immediately, even if you are in the middle of a procedure.

Once the issue is identified and you’re addressing it, silence the alarm. This minimizes stress on both you and the team, and reduces the risk of becoming desensitized to additional alarms that may follow.

See Table 6.1 for common anesthetic complications and strategies to prevent them from “snowballing” into more serious events.

Table 6.1 Common complications you will encounter in your training years, and how to prevent them

Complication	Prevention/Management
Inadvertent arterial puncture during attempt at vascular access.	Most arterial punctures will result in little more than a hematoma, which is reasonably easy to manage by holding pressure.
	However, inadvertent (1) dilation or (2) cannulation of an artery that was meant for a venous access device can be a serious complication, no matter the location. This can result in dissection, exsanguination, stroke, or tissue ischemia.
	This is a useful example of a case in which early signs of failure should be respected. Prior to the dilation or cannulation of a central line, it is essential to verify the venous structure. Various ways, which will be discussed later in this text, include column drop and ultrasound visualization.
	If you do end up dilating or cannulating an artery, never remove the device, as tempting as it may be. In most cases, the complication should be discussed with a vascular surgeon. Removal can cause uncontrolled bleeding and complicate subsequent repair.
	The same goes for a “stuck” wire that will not come out of a vascular access device. Never forcefully remove the wire, as it may be stuck in the vessel. In most cases, you will have to remove both the catheter and the wire at the same time, as the wire may be kinked.
Upper airway trauma	A variety of airway structures can be injured during a forceful or repeated intubation—these include the uvula, tongue, arytenoids, and tonsils (which, if ruptured, can cause significant bleeding). These injuries are more likely when multiple intubation attempts are made, especially in difficult airways.
	The best way to reduce the risk of airway trauma is to limit the number of times you instrument the airway. If direct laryngoscopy (DL) doesn’t yield a good view, switch to a video laryngoscope rather than attempting DL again. Use suction only if it’s clearly necessary to improve your view—aggressive or repeated suctioning can contribute to trauma.
	When advancing the endotracheal tube (ETT), avoid repeatedly “jabbing” toward the cords. Instead, reassess and optimize your view so the tube follows a more controlled, direct path into the trachea.
	Stylets are a common source of airway trauma. Always verify that the stylet does not extend beyond the tip of the endotracheal tube (ETT), as this presents a clear risk of injury. Ideally, the stylet should be removed as the tube enters the trachea and not kept in place as the tube advances further. Depending on the curvature, a stylet can direct the tube anteriorly, potentially causing trauma to the anterior tracheal wall.
	The same principle applies to double-lumen tubes: the stylet should guide the tube toward the glottis but be removed before it enters the trachea. Rigid tubes, such as those used for NIMs monitoring, laser-resistant tubes, and other specialty ETTs, carry an increased risk of injury and should be handled with extra care.
	Airway exchange devices and introducer catheters (e.g., the bougie) can also cause trauma if inserted forcefully or without visualization. Use gentle, controlled movements and be mindful of resistance to avoid damaging airway structures.
Infiltrated IVs	In our world, a functioning IV is a lifeline. A temperamental or sluggish IV is a common annoyance, but an IV that fails completely and goes unrecognized can have serious consequences. Without prompt recognition, a nonfunctioning IV can result in intraoperative awareness due to lack of anesthetic delivery, hypotension from missed vasopressors, and patient movement due to absent opioid or paralytic administration.
	In patients receiving total intravenous anesthesia (TIVA), an undetected IV failure is obviously catastrophic due to the risk of awareness.
	If an IV infiltrates, the buildup of vesicant medications or high volumes of fluid can also cause permanent soft tissue injury.
	Maintaining IV integrity requires constant vigilance. Keep an active inventory of your lines, stopcocks, Y-connectors, and infusion sets. Seasoned providers often instinctively check these, even during brief relief breaks, because a small oversight can have major downstream effects. Always verify that all connections are tight, flows are uninterrupted, and pressures are appropriate.
	Maintain a high index of suspicion for IV failure, particularly when lines were: (1) difficult to place, (2) inserted under ultrasound guidance, or (3) placed in locations where visual assessment is limited, such as the antecubital fossa or external jugular, both of which can conceal significant infiltration.
	In obese patients, extravasation is even harder to detect. Be especially wary of IVs in tucked arms; any resistance to flow or absence of droplets in the IV chamber should trigger immediate concern.
	First, rule out human error: check for a misplaced stopcock or an inflating BP cuff on the same side. Then, inspect the IV visually. This applies even during critical phases of surgery, even if arms are tucked and draped. A functioning IV is essential to patient safety and must be verified when flow is compromised.
Barotrauma and auto-PEEP	Inadvertent delivery of high positive pressure can injure the airways and transiently reduce venous return, resulting in hypotension and a form of “obstructive shock.”
	This can happen if the anesthesia machine is left in manual ventilation mode with the APL (“pop-off”) valve closed. With fresh gas flow running, the reservoir bag inflates beyond its capacity, transmitting pressure to the lungs and causing pulmonary distention. While many patients tolerate this, it can be dangerous in the critically ill. Impaired venous return may lead to hypotension or even cardiac arrest. Patients with severe COPD, pulmonary blebs, or distorted airway anatomy are also at risk of barotrauma or pneumothorax.
	Like an infiltrated IV, this event can occur silently, especially during the busy post-intubation period when attention is diverted to lines, hemodynamics, or positioning. Vigilance is key. Stay aware of your APL valve setting and monitor your ventilator alarms closely.
	“Auto-PEEP” is a form of inadvertent positive pressure buildup that can occur during mechanical ventilation. You should periodically monitor peak and end-expiratory pressures throughout the case. If the respiratory rate is too high or if the patient has obstructive physiology delaying exhalation, the lungs may not fully empty between breaths. This incomplete exhalation leads to trapped air, a phenomenon known as auto-PEEP or “breath stacking.”
	Auto-PEEP is most common in elderly patients with COPD or in ARDS patients ventilated with high rates and high PEEP. As pressure accumulates, airways become overdistended, which can impair venous return, cause hypotension, and even lead to cardiac arrest.
	To prevent auto-PEEP, ensure that the patient has enough time to fully exhale between breaths. A clue is that end-expiratory pressure should return to the set PEEP baseline.
	If an auto-PEEP crisis occurs (often signaled by high peak pressure alarms and hypotension from reduced venous return), the immediate rescue maneuver is to disconnect the patient from the ventilator. This allows full exhalation and restores venous return. Ventilation should then resume with adjustments such as a lower respiratory rate, longer expiratory time, or reduced tidal volume.
Air embolism	Air embolism is a potentially devastating event, especially when it results from a preventable central line error. It can occur when a central line is open to air while the patient is flat or sitting upright, creating a negative intrathoracic pressure gradient that draws air into the venous system.
	Common causes include: an unclamped lumen inadvertently left open to air; improperly rotated stopcocks creating an open-air pathway; and fracture of a central line or Medi-port (can occur during a rocky transport), leaving internal tubing exposed.
	Vigilance with line management and stopcock orientation is essential, particularly during transitions of care and patient movement.
Medication error	At some point in your career, you will make a medication error. With experience, you’ll grow to appreciate the safety checks that prevented it from being far worse.
	In the OR, our safety net is thinner than on the wards. We lack many of the secondary and tertiary barriers: pharmacy review, dispensing systems, nursing checks, and even patient confirmation. Our first and often only defense is the design of the medications themselves: vial size, syringe volume, and labeling. Most drugs are packaged to reduce overdose risk, but there are critical exceptions: phenylephrine 10 mg vials, epinephrine 1 mg vials, insulin, and heparin, among them. These high-risk drugs can come in small containers and undergo frequent labeling design changes, increasing the risk of error.
	You must examine every vial, every time. No shortcuts.
	Many medication errors occur through the “Swiss cheese” model: system flaws line up: missed allergies, wrong medication reconciliations, inaccurate surgical plans. The anesthesia provider is often the last stop before harm. You are the final barrier. Never rely on another provider to catch a mistake you could prevent.
	The following are examples of medication errors, grouped by type:
	Wrong Route Heparin given IV instead of subcutaneously Provider gave 5,000 units IV due to habit since he had just been doing a vascular surgery rotation, which involved a lot of IV heparin. Phenylephrine connected to epidural instead of bupivacaine A 20 mL syringe, assumed to be bupivacaine, was connected to an epidural catheter. It was later discovered to be phenylephrine. The reverse of this mistake—connecting a local anesthetic to an IV—could be fatal.
	Wrong Dose Insulin overdose due to concentration change Provider assumed the insulin bag was 1 unit/mL, unaware that the pharmacy had changed to a 100 units/mL formulation. Phenylephrine overdose from a mislabeled syringe Provider administered double the intended dose because the previous provider loaded 80 mcg/mL instead of the expected 40 mcg/mL, and the label wasn’t carefully checked.
	Wrong Medication Phenylephrine given instead of ondansetron A 10 mg vial of phenylephrine was mistaken for ondansetron due to its similar appearance and proximity in the workspace. Atropine given instead of dexamethasone A provider misidentified a pink-labeled dexamethasone vial (atropine can also come in pink vials). Cefoxitin administered instead of vancomycin A leftover antibiotic bag from a previous case was not checked, and the wrong drug was given.
	Wrong Thought Process Incorrect blood pressure due to transducer position A transducer placed 2 feet above the patient displayed falsely elevated BP, prompting an unnecessary phenylephrine infusion and workup for hypotension. The error was due to a mispositioned transducer. Heparin given during surgery for bleeding A provider administered heparin per a pre-op order without recognizing that the surgery was being performed to control active bleeding. Ketorolac given despite severe renal impairment Out of habit, a provider gave 30 mg of ketorolac, overlooking the patient’s current hypovolemia, AKI, and history of chronic kidney disease.
	The common thread in all of these errors is autopilot. A provider becomes accustomed to giving a specific drug, in a familiar vial, at a familiar dose, at a familiar point in the case, failing to recognize a subtle but critical change in context.
	Wrong-dose errors are particularly common when transitioning between practice settings: for example, from adult to pediatric care, where drug concentrations may differ significantly. It’s dangerous to assume that every medication has been prepared the way you’re “used to.”
	The only true safeguard against medication error is deliberate thought. Before administering any drug, ask yourself: What am I giving? Is this the correct drug and dose for this specific patient? Are there any clinical or procedural reasons not to give it right now? Get out of autopilot. The safest anesthesiologist is the one who slows down enough to think.