Looks like we got ourselves a Bleeder

 

The Post-Partum Hemorrhage: Notes from Anesthesiology Core Review Part Two Advanced Exam

most common cause of blood loss in OB practice
leading cause of fetal and maternal M&M globally
definition: bleeding w/in 6wks of delivery
->500ml for vaginal, >1000ml for c/s
-decrease of 10% in hct from admission
-often underestimated!
Uterine blood flow = 700ml/min
-get good access fast
Uterine Atony
2-5% of all deliversies
cause of >90% of pp hemorrhage
results from failure of uterus to contract
risk factors:
-multiparity
-macrosomia
-polyhydramnios
-long labor (+oxytocin)
-chorioamnionitis
-placenta: retained, accreta, increta, percreta
-poor perfused myometrium
-drugs: inhalationals, oxytocin, tocolytics
Management of Atony
Oxytocin to contract uterus
-rapid: hypotension, decrease svr, tachy (rare card collapse), chest pain, ischemia, anaphylaxis
-ECG changes resolve spontaneously
-similar to ADH, so watch for water intox. so never give with hypotonic solution!
Ergot Alkaloids
-0.4mg – methylergonovine IM only
-10 minutes to action, lasts 3-6hrs
-vasoconstrictive -> HTN, avoid with pre-eclempsia.eclampsia
-if given IV -> intense vasoconstric -> siezures, CVA, retinal detach – MI
-Common ade: nausea vomiting
-2 dose then move on
Prostaglandins
-increase calcium -> myosin kinase

-carboprost = 15-methyl prostaglandin f2alpha given 260ucg IM
-increase force/interval of contraction
-also don’t give IV
-side effects: diarrhea, HTN, fever, flush, tachy
-bronchospasm, pulmonary vasoconstriction – so careful with asthmatics
-Misoprostol (prostaglandin E1) oral, rectal intrauterine also effective, side effect hypothermia
Retained Placenta

1-3 in 100 deliveries

result: uterus unable to fully contract –> bleeding

Need for uterine relaxation to explore and fix

GA -> 1MAC+ Inhalational

IV or sublingual Nitorglycerin
-100 ug works in 30-45seconds
-60-90 seconds return to baseline, may need redosing
-tx hypotension with phenylephrine

The Abnormal Placenta

Normal interface between placenta and uterus : Decidua basalis
When that’s missing -> uteri gets implanted
Placenta Accreta = ON myometrium
Placenta Increta = IN myometrium
Placenta Perceta = through and to other organs!
Bleeding serious complication and common
1:2000 births have accreta
-prior c/s
-placenta previa
-more c/s higher risk

If known beforehand, discuss plan about possible hysterectomy
-this can incur massive blood loss
-cell saver, think general anesthesia, secure airway, arterial line
-also consider prophylactic internal iliac balloon catheters in IR preop

Genital Trauma

lacerations of cervix, vagina, perinuem most common injuries of childbirth
if continued hypotension: think retriperitoneal hematoma!
-CT or MRI, tx with ex lap

help along repair with IV meds, neuraxial continuation, or nitrous oxide, think low dose ketamine too

Why Shiver?

Girlfriend To Stay Underneath Blanket For Next 5 Months
Girlfriend To Stay Underneath Blanket For Next 5 Months

Notes from Truelearn and UpToDate on Shivering in OB

Shivering during labor

  • 10-20% of laboring patients without epidural, 30-55% with epidural
  • multifactorial
  • hormonal changes: less progesterone than normal cycle results in less NE -> less augmentation of core temps
  • immunological reaction to fetomaternal transfusion
  • use of Misoprostol
  • possibly non-thermogenic: bursting tremor similar to clonus
  • Epidural shivering from central hypothermia and peripheral vasoconstriction
  • First hour with an epidural: core heat -> periphery 2/2 neuraxial blunt autonomic thermoregulatory below level of blockade, vasodilation causes redistribution of heat

Prevention and Treatment

  • Warming prior to epidural/spinal placement can decrease shivering
  • Warming after shivering
  • Dopaminergic/seretonergic pathway drugs can reduce shivering (25mg IV Meperidine (demerol), clonidine, tramadol, ketamine, dexmedatomidine)

BANG BANG

What is OSA? Why does OSA matter? And does STOP BANG help us truly identify OSA?

OSA is:

  • cessation of airflow >10sec, 5+x/hr + 4% desat in SaO2
  • definitions vary, but >15x /hr is diagnostistic
  • dx by polysomnography
  • Apnea/hypopnea index (AHI), which is derived from the total number of apneas and hypopneas divided by the total sleep time (mild up to 15, severe >30)

 

Obstructive Sleep Apnea (OSA) matters because:

  • harder to intubate, harder to ventilate
  • increased prevalance of cardiac disease: Afib, arrhythmias, stroke, CHF, cardiomyopathy, pulmonary hypertension, CAD
  • periop complications higher, including airway obstruction, hypoxemia, atelectasis, pneumonia
  • more sensitive to respiratory depressant effect of opioids and hypnotics

Source: http://www.ncbi.nlm.nih.gov/pubmed/18339794

Is STOP BANG Helpful?

The literature shows…

“The sensitivities of the STOP questionnaire with apnea-hypopnea index greater than 5, greater than 15, and greater than 30 as cutoffs were 65.6, 74.3, and 79.5%, respectively. When incorporating body mass index, age, neck circumference, and gender into the STOP questionnaire, sensitivities were increased to 83.6, 92.9, and 100% with the same apnea-hypopnea index cutoffs.”

See: http://www.ncbi.nlm.nih.gov/pubmed/18431116

And what are these complications?

Mostly pulmonary, with a few possible cardiac events mixed in as noted in this study in Chest, cited in Miller’s 8th edition( http://journal.publications.chestnet.org/article.aspx?articleid=1085863#t4)

 

Variables ODI4% Age, yr Sex BMI, kg/m2 Type of Surgery Complication
ODI 4%< 5 0.2 27 F 46.7 Laparoscopic gastric bypass surgery Transient episodes of unspecified tachyarrhythmia during the first 3 postoperative days
3.0 52 F 59.4 Laparoscopy with conversion to open ventral herniorrhaphy and adhesiolysis Hypoxemia treated with supplemental oxygen and BPAP
ODI 4%≥ 5 5.5 49 F 26.2 Total abdominal hysterectomy and right salpingoophorectomy cystoscopy with placement of ureteral catheters Hypoxemia was observed on postoperative day 3 and treated with oxygen supplementation; atelectasis was noted
6.0 49 F 39.1 Total abdominal hysterectomy and bilateral oophorectomy Intraperitoneal bleeding was treated with embolization
6.2 39 F 44.9 Laparoscopic gastric bypass surgery Intraperitoneal bleeding which resolved without surgery
7.6 61 M 33.5 Sigmoid colon resection Hypoxemia and hypotension.
12.9 64 M 37.0 Mitral valve replacement Hypotension and junctional escape rhythm
13.0 57 M 38.9 Laparoscopic colonic polypectomy Atelectasis
14.5 58 F 41.6 Total abdominal hysterectomy and bilateral oophorectomy Atelectasis
18.6 62 M 37.3 Left inguinal herniorrhaphy Wheezing observed which required treatment with bronchodilators
24.6 49 F 28.1 Total abdominal hysterectomy and bilateral oophorectomy Pneumonia
26.3 53 F 47.9 Gastric bypass surgery GI bleeding
31.9 50 M 29.6 Radical prostatectomy Hypoxemia treated with CPAP
34.1 62 F 31.4 Total abdominal hysterectomy and bilateral oophorectomy Atelectasis
34.2 69 M 36.9 Laparoscopic right hemicolectomy Pulmonary embolism; superior mesenteric vein thrombosis
36.4 55 F 49.5 Exploratory laparotomy, adhesiolysis, small bowel resection, partial hepatic resection, gastric bypass Chest pain (MI was ruled out)
82.4 66 F 46.8 Total abdominal hysterectomy and bilateral oophorectomy Hypoxemia treated with CPAP

*

F = female; M = male; BPAP = bilevel positive airway pressure. See Table 1 for abbreviation not used in the text.

Dry Lungs?

Fluid in Thoracic Surgery: Time to move overthrow Immortan Joe?
Fluid in Thoracic Surgery: Time to overthrow Immortan Joe?

The Classic Teaching from Miller 8th Edition ch 66 Anesthesia for Thoracic Surgery

Total positive fluid balance in the first 24-hour perioperative period should not exceed 20 mL/kg.

For an average adult patient, crystalloid administration should be limited to less than 3 L in the first 24 hours.

No fluid administration for third-space fluid losses during pulmonary resection.

Urine output greater than 0.5 mL/kg/h is unnecessary.

If increased tissue perfusion is needed postoperatively, it is preferable to use invasive monitoring and inotropes rather than to cause fluid overload.

And so the above was also consistent with the clinical teaching at my institution. Keep them dry, regardless of whether it was a wedge resection, lobectomy or esophagectomy (I haven’t had the pleasure of a pneumonectomy yet).

But further reading in Barash (Clinical Anethesia Fundamentals), calls this into question in ch 34 Anesthesia for Thoracic Surgery, with the following one liner broadside:

“Fluid management for all thoracic procedures should follow either a restricted or a goal-directed protocol. However, recently, concerns about acute kidney injury have called into question the strategy of fluid restriction in thoracic surgery.”

And later in the same chapter, a “Did You Know?” sidebar reinforces the same point, specifically mentioning esophageal surgery and the controversy around restrictive fluid management.

When asked about this in the operating room, the Thoracic Surgery team even indicated that anesthesiologists in this practice are being too restrictive, especially with the esophagectomies (which are for the most part, abdominal surgery).

So what is one to make of this?

Digging into the literature, there was a nice summary of the controversy and recent data at Current Opinion in Anaesthesiology  (doi: 10.1097/ACO.0b013e32835c5cf5) from a team of anesthesiologists at Yale. The article provides a nice run down on the basis of the fluid restrictive strategies (mainly studies from the 198os) and how these studies were performed before the advent of lung protective ventilation strategies (6-8cc/kg and use of peep). They do agree that fluid restriction in Pneumonectomy is logical:

In pneumonectomy, the whole cardiac output will be directed to the remaining lung. This volume in the presence of a decreased vital capacity may overwhelm the remaining lung’s protective mechanisms resulting in a rise in the pulmonary capillary filtration pressure.

However, this may not be the case in lesser lung resections, with a restrictive therapy threatening to cause Acute Kidney Injury. In fact, the belief that renal injury is low in thoracic surgery appears misplaced, as old data only counted kidney injury if patients required renal replacement therapy. Newer evidence shows thoracic patients are at higher risk of AKI than previously thought and that this may cause increased M&M in the longer term.

The authors then go on to promote a Normovolemia and Goal-Directed fluid therapy regiment. One study showed a simple normovolemia method of replacing ongoing losses and use of maintenance fluids i/o and post-op until PO intake, reduced both AKI and extravascular lung water (EVLW). The goal-directed therapy targets Cardiac Index through either Thermodilution, PiCCO, Transesophageal Doppler, SVV or PPV.  The authors point out that while controversy remains, there is some evidence showing no increase in EVLW with goal-directed fluid therapy when lung protective ventilation strategies are used.

The remainder of the article goes into the colloid vs. crystalloid debate, which is beyond the scope of this post, and it appears there is no evidence of which is better to use in thoracic surgery (potential for future research questions!).

So in conclusion, it appears that Dry Lungs may not be the Best Lungs and Best Kidneys for Thoracic Surgery.

Renal Replacement Therapy – Considerations

Indications for Renal Replacement Therapy (notes from TrueLearn)

-broad term : hemodialysis, peritoneal dialysis, hemofiltration, renal transplant
-CRRT is over 24hrs, best for HD unstable patients

Chronic Renal Failure indications
-fluid overload
-uremic symptoms
-ftt
-malnutrition
-GFR criteria

Indications in ICU patient
-oliguria/anuria
-pulmonary edema unresponsive to diuretics
-uncompensated metabolic acidosis (ph35, creatinine >400, hyperkalemia >6.5

Succ will raise K same as normal patient
watch fluid status and hemodynamics
avoid nephrotoxic agents (some a/b, nsaids)

PICC vs central line: not that clear cut 

From Patient Safety Solutions: http://www.patientsafetysolutions.com/docs/January_21_2014_The_PICC_Myth.htm

PICC lines (peripherally inserted central catheter)  are often seen as a lower risk alternative to central lines for patients with difficulty iv access, however this is a myth and piccs are not without risk including:

  • Higher risk of upper extremity dvt (2.55 or and account for 35% of all ue dvt)
  • Similar risk of infection!  Meta analysis and systematic reviews show no sig diff in clabsi! 
  • Other complications include thrombophlebitis,and dysfx and malpositioning greater for PICC than central line 

These concerns prompted the ABIM choosing wisely campaign to include piccs on their list of treatments to question:

Don’t place, or leave in place, peripherally inserted central catheters for patient or provider convenience.

Peripherally inserted central catheters (or “PICCs”) are commonly used devices in contemporary medical practice that are associated with two costly and potentially lethal health care-acquired complications: central-line associated bloodstream infection (CLABSI) and venous thromboembolism (VTE). Given the clinical and economic consequences of these complications, placement of PICCs should be limited to acceptable indications (long-term intravenous antibiotics, total parenteral nutrition, chemotherapy and frequent blood draws). PICCs should be promptly removed when acceptable indications for their use ends.

So next time someone recommends a PICC over a central line, think about the indications and necessity!